64tass v1.55 r2176 reference manual

This is the manual for 64tass, the multi pass optimizing macro assembler for
the 65xx series of processors. Key features:

  * Open source portable C with minimal dependencies
  * Familiar syntax to Omicron TASS and TASM
  * Supports 6502, 65C02, R65C02, W65C02, 65CE02, 65816, DTV, 65EL02, 4510
  * Arbitrary-precision integers and bit strings, double precision floating
    point numbers
  * Character and byte strings, array arithmetic
  * Handles UTF-8, UTF-16 and 8 bit RAW encoded source files, Unicode character
    strings
  * Supports Unicode identifiers with compatibility normalization and optional
    case insensitivity
  * Built-in `linker' with section support
  * Various memory models, binary targets and text output formats (also Hex/
    S-record)
  * Assembly and label listings available for debugging or exporting
  * Conditional compilation, macros, structures, unions, scopes

Contrary how the length of this document suggests 64tass can be used with just
basic 6502 assembly knowledge in simple ways like any other assembler. If some
advanced functionality is needed then this document can serve as a reference.

This is a development version. Features or syntax may change as a result of
corrections in non-backwards compatible ways in some rare cases. It's difficult
to get everything `right' first time.

Project page: https://sourceforge.net/projects/tass64/

The page hosts the latest and older versions with sources and a bug and a
feature request tracker.

-------------------------------------------------------------------------------

Table of Contents

  * Table of Contents
  * Usage tips
  * Expressions and data types
      + Integer constants
      + Bit string constants
      + Floating point constants
      + Character string constants
      + Byte string constants
      + Lists and tuples
      + Dictionaries
      + Code
      + Addressing modes
      + Uninitialized memory
      + Booleans
      + Types
      + Symbols
          o Regular symbols
          o Local symbols
          o Anonymous symbols
          o Constant and re-definable symbols
          o The star label
      + Built-in functions
          o Mathematical functions
          o Other functions
      + Expressions
          o Operators
          o Comparison operators
          o Bit string extraction operators
          o Conditional operators
          o Address length forcing
          o Compound assignment
          o Slicing and indexing
  * Compiler directives
      + Controlling the compile offset and program counter
      + Dumping data
          o Storing numeric values
          o Storing string values
      + Text encoding
      + Structured data
          o Structure
          o Union
          o Combined use of structures and unions
      + Macros
          o Parameter references
          o Text references
      + Custom functions
      + Conditional assembly
          o If, else if, else
          o Switch, case, default
          o Comment
      + Repetitions
      + Including files
      + Scopes
      + Sections
      + 65816 related
      + Controlling errors
      + Target
      + Misc
      + Printer control
  * Pseudo instructions
      + Aliases
      + Always taken branches
      + Long branches
  * Original turbo assembler compatibility
      + How to convert source code for use with 64tass
      + Differences to the original turbo ass macro on the C64
      + Labels
      + Expression evaluation
      + Macros
      + Bugs
  * Command line options
      + Output options
      + Operation options
      + Diagnostic options
      + Target selection on command line
      + Symbol listing
      + Assembly listing
      + Other options
      + Command line from file
  * Messages
      + Warnings
      + Errors
      + Fatal errors
  * Credits
  * Default translation and escape sequences
      + Raw 8-bit source
          o The none encoding for raw 8-bit
          o The screen encoding for raw 8-bit
      + Unicode and ASCII source
          o The none encoding for Unicode
          o The screen encoding for Unicode
  * Opcodes
      + Standard 6502 opcodes
      + 6502 illegal opcodes
      + 65DTV02 opcodes
      + Standard 65C02 opcodes
      + R65C02 opcodes
      + W65C02 opcodes
      + W65816 opcodes
      + 65EL02 opcodes
      + 65CE02 opcodes
      + CSG 4510 opcodes
  * Appendix
      + Assembler directives
      + Built-in functions
      + Built-in types

-------------------------------------------------------------------------------

Usage tips

64tass is a command line assembler, the source can be written in any text
editor. As a minimum the source filename must be given on the command line. The
`-a' command line option is highly recommended if the source is Unicode or
ASCII.

64tass -a src.asm

There are also some useful parameters which are described later.

For comfortable compiling I use such `Makefile's (for make):

demo.prg: source.asm macros.asm pic.drp music.bin
        64tass -C -a -B -i source.asm -o demo.tmp
        pucrunch -ffast -x 2048 demo.tmp >demo.prg

This way `demo.prg' is recreated by compiling `source.asm' whenever
`source.asm', `macros.asm', `pic.drp' or `music.bin' had changed.

Of course it's not much harder to create something similar for win32
(make.bat), however this will always compile and compress:

64tass.exe -C -a -B -i source.asm -o demo.tmp
pucrunch.exe -ffast -x 2048 demo.tmp >demo.prg

Here's a slightly more advanced Makefile example with default action as testing
in VICE, clean target for removal of temporary files and compressing using an
intermediate temporary file:

all: demo.prg
        x64 -autostartprgmode 1 -autostart-warp +truedrive +cart $<

demo.prg: demo.tmp
        pucrunch -ffast -x 2048 $< >$@

demo.tmp: source.asm macros.asm pic.drp music.bin
        64tass -C -a -B -i $< -o $@

.INTERMEDIATE: demo.tmp
.PHONY: all clean
clean:
        $(RM) demo.prg demo.tmp

It's useful to add a basic header to your source files like the one below, so
that the resulting file is directly runnable without additional compression:

*       = $0801
        .word (+), 2005  ;pointer, line number
        .null $9e, format("%d", start);will be sys 4096
+       .word 0          ;basic line end

*       = $1000

start   rts

A frequently coming up question is, how to automatically allocate memory,
without hacks like *=*+1? Sure there's .byte and friends for variables with
initial values but what about zero page, or RAM outside of program area? The
solution is to not use an initial value by using `?' or not giving a fill byte
value to .fill.

*       = $02
p1      .addr ?         ;a zero page pointer
temp    .fill 10        ;a 10 byte temporary area

Space allocated this way is not saved in the output as there's no data to save
at those addresses.

What about some code running on zero page for speed? It needs to be relocated,
and the length must be known to copy it there. Here's an example:

        ldx #size(zpcode)-1;calculate length
-       lda zpcode,x
        sta wrbyte,x
        dex             ;install to zero page
        bpl -
        jsr wrbyte
        rts
;code continues here but is compiled to run from $02
zpcode  .logical $02
wrbyte  sta $ffff       ;quick byte writer at $02
        inc wrbyte+1
        bne +
        inc wrbyte+2
+       rts
        .here

The assembler supports lists and tuples, which does not seems interesting at
first as it sound like something which is only useful when heavy scripting is
involved. But as normal arithmetic operations also apply on all their elements
at once, this could spare quite some typing and repetition.

Let's take a simple example of a low/high byte jump table of return addresses,
this usually involves some unnecessary copy/pasting to create a pair of tables
with constructs like >(label-1).

jumpcmd lda hibytes,x   ; selected routine in X register
        pha
        lda lobytes,x   ; push address to stack
        pha
        rts             ; jump, rts will increase pc by one!
; Build a list of jump addresses minus 1
_       := (cmd_p, cmd_c, cmd_m, cmd_s, cmd_r, cmd_l, cmd_e)-1
lobytes .byte <_        ; low bytes of jump addresses
hibytes .byte >_        ; high bytes

There are some other tips below in the descriptions.

-------------------------------------------------------------------------------

Expressions and data types

Integer constants

Integer constants can be entered as decimal digits of arbitrary length. An
underscore can be used between digits as a separator for better readability of
long numbers. The following operations are accepted:

            Integer operators and functions
x + y    add x to y                       2 + 2 is 4
x - y    subtract y from x                4 - 1 is 3
x * y    multiply x with y                2 * 3 is 6
x / y    integer divide x by y            7 / 2 is 3
x % y    integer modulo of x divided by y 5 % 2 is 1
x ** y   x raised to power of y           2 ** 4 is 16
-x       negated value                    -2 is -2
+x       unchanged                        +2 is 2
~x       -x - 1                           ~3 is -4
x | y    bitwise or                       2 | 6 is 6
x ^ y    bitwise xor                      2 ^ 6 is 4
x & y    bitwise and                      2 & 6 is 2
x << y   logical shift left               1 << 3 is 8
x >> y   arithmetic shift right           -8 >> 3 is -1

Integers are automatically promoted to float as necessary in expressions. Other
types can be converted to integer using the integer type int.

        .byte 23        ; as unsigned
        .char -23       ; as signed

; using negative integers as immediate values
        ldx #-3         ; works as '#-' is signed immediate
num     = -3
        ldx #+num       ; needs explicit '#+' for signed 8 bits

        lda #((bitmap >> 10) & $0f) | ((screen >> 6) & $f0)
        sta $d018

Bit string constants

Bit string constants can be entered in hexadecimal form with a leading dollar
sign or in binary with a leading percent sign. An underscore can be used
between digits as a separator for better readability of long numbers. The
following operations are accepted:

       Bit string operators and functions
~x     invert bits         ~%101 is ~%101
y .. x concatenate bits    $a .. $b is $ab
y x n  repeat              %101 x 3 is %101101101
x[n]   extract bit(s)      $a[1] is %1
x[s]   slice bits          $1234[4:8] is $3
x | y  bitwise or          ~$2 | $6 is ~$0
x ^ y  bitwise xor         ~$2 ^ $6 is ~$4
x & y  bitwise and         ~$2 & $6 is $4
x << y bitwise shift left  $0f << 4 is $0f0
x >> y bitwise shift right ~$f4 >> 4 is ~$f

Length of bit string constants are defined in bits and is calculated from the
number of bit digits used including leading zeros.

Bit strings are automatically promoted to integer or floating point as
necessary in expressions. The higher bits are extended with zeros or ones as
needed.

Bit strings support indexing and slicing. This is explained in detail in
section `Slicing and indexing'.

Other types can be converted to bit string using the bit string type bits.

        .byte $33       ; 8 bits in hexadecimal
        .byte %00011111 ; 8 bits in binary
        .text $1234     ; $34, $12 (little endian)

        lda $01
        and #~$07       ; 8 bits even after inversion
        ora #$05
        sta $01

        lda $d015
        and #~%00100000 ;clear a bit
        sta $d015

Floating point constants

Floating point constants have a radix point in them and optionally an exponent.
A decimal exponent is `e' while a binary one is `p'. An underscore can be used
between digits as a separator for better readability. The following operations
can be used:

             Floating point operators and functions
x + y       add x to y                       2.2 + 2.2 is 4.4
x - y       subtract y from x                4.1 - 1.1 is 3.0
x * y       multiply x with y                1.5 * 3 is 4.5
x / y       integer divide x by y            7.0 / 2.0 is 3.5
x % y       integer modulo of x divided by y 5.0 % 2.0 is 1.0
x ** y      x raised t power of y            2.0 ** -1 is 0.5
-x          negated value                    -2.0 is -2.0
+x          unchanged                        +2.0 is 2.0
~x          almost -x                        ~2.1 is almost -2.1
x | y       bitwise or                       2.5 | 6.5 is 6.5
x ^ y       bitwise xor                      2.5 ^ 6.5 is 4.0
x & y       bitwise and                      2.5 & 6.5 is 2.5
x << y      logical shift left               1.0 << 3.0 is 8.0
x >> y      arithmetic shift right           -8.0 >> 4 is -0.5

As usual comparing floating point numbers for (non) equality is a bad idea due
to rounding errors.

The only predefined constant is pi.

Floating point numbers are automatically truncated to integer as necessary.
Other types can be converted to floating point by using the type float.

Fixed point conversion can be done by using the shift operators. For example a
8.16 fixed point number can be calculated as (3.14 << 16) & $ffffff. The binary
operators operate like if the floating point number would be a fixed point one.
This is the reason for the strange definition of inversion.

        .byte 3.66e1       ; 36.6, truncated to 36
        .byte $1.8p4       ; 4:4 fixed point number (1.5)
        .sint 12.2p8       ; 8:8 fixed point number (12.2)

Character string constants

Character strings are enclosed in single or double quotes and can hold any
Unicode character.

Operations like indexing or slicing are always done on the original
representation. The current encoding is only applied when it's used in
expressions as numeric constants or in context of text data directives.

Doubling the quotes inside string literals escapes them and results in a single
quote.

    Character string operators and functions
y .. x concatenate strings  "a" .. "b" is "ab"
y in x is substring of      "b" in "abc" is true
a x n  repeat               "ab" x 3 is "ababab"
a[i]   character from start "abc"[1] is "b"
a[i]   character from end   "abc"[-1] is "c"
a[s]   no change            "abc"[:] is "abc"
a[s]   cut off start        "abc"[1:] is "bc"
a[s]   cut off end          "abc"[:-1] is "ab"
a[s]   reverse              "abc"[::-1] is "cba"

Character strings are converted to integers, byte and bit strings as necessary
using the current encoding and escape rules. For example when using a sane
encoding "z"-"a" is 25.

Other types can be converted to character strings by using the type str or by
using the repr and format functions.

Character strings support indexing and slicing. This is explained in detail in
section `Slicing and indexing'.

mystr   = "oeU"         ; character string constant
        .text 'it''s'   ; it's
        .word "ab"+1    ; conversion result is "bb" usually

        .text "text"[:2]     ; "te"
        .text "text"[2:]     ; "xt"
        .text "text"[:-1]    ; "tex"
        .text "reverse"[::-1]; "esrever"

Byte string constants

Byte strings are like character strings, but hold bytes instead of characters.

Quoted character strings prefixing by `b', `l', `n', `p', `s', `x' or `z'
characters can be used to create byte strings. The resulting byte string
contains what .text, .shiftl, .null, .ptext and .shift would create. Direct
hexadecimal entry can be done using the `x' prefix and `z' denotes a z85
encoded byte string.

          Byte string operators and functions
y .. x concatenate strings x"12" .. x"34" is x"1234"
y in x is substring of     x"34" in x"1234" is true
a x n  repeat              x"ab" x 3 is x"ababab"
a[i]   byte from start     x"abcd12"[1] is x"cd"
a[i]   byte from end       x"abcd"[-1] is x"cd"
a[s]   no change           x"abcd"[:] is x"abcd"
a[s]   cut off start       x"abcdef"[1:] is x"cdef"
a[s]   cut off end         x"abcdef"[:-1] is x"abcd"
a[s]   reverse             x"abcdef"[::-1] is x"efcdab"

Byte strings support indexing and slicing. This is explained in detail in
section `Slicing and indexing'.

Other types can be converted to byte strings by using the type bytes.

        .enc "screen"   ;use screen encoding
mystr   = b"oeU"        ;convert text to bytes, like .text
        .enc "none"     ;normal encoding

        .text mystr     ;text as originally encoded
        .text s"p1"     ;convert to bytes like .shift
        .text l"p2"     ;convert to bytes like .shiftl
        .text n"p3"     ;convert to bytes like .null
        .text p"p4"     ;convert to bytes like .ptext

Binary data may be embedded in source code by using hexadecimal byte strings.
This is more compact than using .byte followed by a lot of numbers. As expected
1 byte becomes 2 characters.

        .text x"fce2"   ;2 bytes: $fc and $e2 (big endian)

If readability is not a concern then the more compact z85 encoding may be used
which encodes 4 bytes into 5 characters. Data lengths not a multiple of 4 are
handled by omitting leading zeros in the last group.

        .text z"FiUj*2M$hf";8 bytes: 80 40 20 10 08 04 02 01

For data lengths of multiple of 4 bytes any z85 encoder will do. Otherwise the
simplest way to encode a binary file into a z85 string is to create a source
file which reads it using the line `label = binary('filename')'. Now if the
labels are listed to a file then there will be a z85 encoded definition for
this label.

Lists and tuples

Lists and tuples can hold a collection of values. Lists are defined from values
separated by comma between square brackets [1, 2, 3], an empty list is [].
Tuples are similar but are enclosed in parentheses instead. An empty tuple is
(), a single element tuple is (4,) to differentiate from normal numeric
expression parentheses. When nested they function similar to an array.
Currently both types are immutable.

          List and tuple operators and functions
y .. x   concatenate lists    [1] .. [2] is [1, 2]
y in x   is member of list    2 in [1, 2, 3] is true
a x n    repeat               [1, 2] x 2 is [1, 2, 1, 2]
a[i]     element from start   ("1", 2)[1] is 2
a[i]     element from end     ("1", 2, 3)[-1] is 3
a[s]     no change            (1, 2, 3)[:] is (1, 2, 3)
a[s]     cut off start        (1, 2, 3)[1:] is (2, 3)
a[s]     cut off end          (1, 2.0, 3)[:-1] is (1, 2.0)
a[s]     reverse              (1, 2, 3)[::-1] is (3, 2, 1)
*a       convert to arguments format("%d: %s", *mylist)
... op a left fold            ... + (1, 2, 3) is ((1+2)+3)
a op ... right fold           (1, 2, 3) - ... is (1-(2-3))

Arithmetic operations are applied on the all elements recursively, therefore
[1, 2] + 1 is [2, 3], and abs([1, -1]) is [1, 1].

Arithmetic operations between lists are applied one by one on their elements,
so [1, 2] + [3, 4] is [4, 6].

When lists form an array and columns/rows are missing the smaller array is
stretched to fill in the gaps if possible, so [[1], [2]] * [3, 4] is [[3, 4],
[6, 8]].

Lists and tuples support indexing and slicing. This is explained in detail in
section `Slicing and indexing'.

mylist  = [1, 2, "whatever"]
mytuple = (cmd_e, cmd_g)

mylist  = ("e", cmd_e, "g", cmd_g, "i", cmd_i)
keys    .text mylist[::2]    ; keys ("e", "g", "i")
call_l  .byte <mylist[1::2]-1; routines (<cmd_e-1, <cmd_g-1, <cmd_i-1)
call_h  .byte >mylist[1::2]-1; routines (>cmd_e-1, >cmd_g-1, >cmd_i-1)

Folding is done on pair of elements either forward (left) or reverse (right).
The list must contain at least one element. Here are some folding examples:

minimum = size([part1, part2, part3]) <? ...
maximum = size([part1, part2, part3]) >? ...
sum     = size([part1, part2, part3]) + ...
xorall  = list_of_numbers ^ ...
join    = list_of_strings .. ...
allbits = sprites.(left, middle, right).bits | ...
all     = [true, true, true, true] && ...
any     = [false, false, false, true] || ...

The range(start, end, step) built-in function can be used to create lists of
integers in a range with a given step value. At least the end must be given,
the start defaults to 0 and the step to 1. Sounds not very useful, so here are
a few examples:

;Bitmask table, 8 bits from left to right
        .byte %10000000 >> range(8)
;Classic 256 byte single period sinus table with values of 0-255.
        .byte 128 + 127.5 * sin(range(256) * rad(360.0/256))
;Screen row address tables
_       := $400 + range(0, 1000, 40)
scrlo   .byte <_
scrhi   .byte >_

Dictionaries

Dictionaries are unsorted lists holding key and value pairs. Definition is done
by collecting key:value pairs separated by comma between braces {1:"value",
"key":1, :"optional default value"}.

Looking up a non existing key is normally an error unless a default value is
given. An empty dictionary is {}. Currently this type is immutable. Numeric and
string keys are accepted, the value can be anything.

  Dictionary operators and functions
x[i]   value lookup {"1":2}["1"] is 2
y in x is a key     1 in {1:2} is true

; Simple lookup
        .text {1:"one", 2:"two"}[2]; "two"
; 16 element "fader" table 1->15->12->11->0
        .byte {1:15, 15:12, 12:11, :0}[range(16)]

Code

Code holds the result of compilation in binary and other enclosed objects. In
an arithmetic operation it's used as the numeric address of the memory where it
starts. The compiled content remains static even if later parts of the source
overwrite the same memory area.

Indexing and slicing of code to access the compiled content might be
implemented differently in future releases. Use this feature at your own risk
for now, you might need to update your code later.

        Label operators and functions
a.b  member                  label.locallabel
a[i] element from start      label[1]
a[i] element from end        label[-1]
a[s] copy as tuple           label[:]
a[s] cut off start, as tuple label[1:]
a[s] cut off end, as tuple   label[:-1]
a[s] reverse, as tuple       label[::-1]

mydata  .word 1, 4, 3
mycode  .block
local   lda #0
        .bend

        ldx #size(mydata) ;6 bytes (3*2)
        ldx #len(mydata)  ;3 elements
        ldx #mycode[0]    ;lda instruction, $a9
        ldx #mydata[1]    ;2nd element, 4
        jmp mycode.local  ;address of local label

Addressing modes

Addressing modes are used for determining addressing modes of instructions.

For indexing there must be no white space between the comma and the register
letter, otherwise the indexing operator is not recognized. On the other hand
put a space between the comma and a single letter symbol in a list to avoid it
being recognized as an operator.

  Addressing mode operators
#  immediate
#+ signed immediate
#- signed immediate
(  indirect
[  long indirect
,b data bank indexed
,d direct page indexed
,k program bank indexed
,r data stack pointer indexed
,s stack pointer indexed
,x x register indexed
,y y register indexed
,z z register indexed

Parentheses are used for indirection and square brackets for long indirection.
These operations are only available after instructions and functions to not
interfere with their normal use in expressions.

Several addressing mode operators can be combined together. Currently the
complexity is limited to 4 operators. This is enough to describe all addressing
modes of the supported CPUs.

                  Valid addressing mode operator combinations
#             immediate                             lda #$12
#+            signed immediate                      lda #+127
#-            signed immediate                      lda #-128
#addr,#addr   move                                  mvp #5,#6
addr          direct or relative                    lda $12 lda $1234 bne $1234
bit,addr      direct page bit                       rmb 5,$12
bit,addr,addr direct page bit relative jump         bbs 5,$12,$1234
(addr)        indirect                              lda ($12) jmp ($1234)
(addr),y      indirect y indexed                    lda ($12),y
(addr),z      indirect z indexed                    lda ($12),z
(addr,x)      x indexed indirect                    lda ($12,x) jmp ($1234,x)
[addr]        long indirect                         lda [$12] jmp [$1234]
[addr],y      long indirect y indexed               lda [$12],y
#addr,b       data bank indexed                     lda #0,b
#addr,b,x     data bank x indexed                   lda #0,b,x
#addr,b,y     data bank y indexed                   lda #0,b,y
#addr,d       direct page indexed                   lda #0,d
#addr,d,x     direct page x indexed                 lda #0,d,x
#addr,d,y     direct page y indexed                 ldx #0,d,y
(#addr,d)     direct page indirect                  lda (#$12,d)
(#addr,d,x)   direct page x indexed indirect        lda (#$12,d,x)
(#addr,d),y   direct page indirect y indexed        lda (#$12,d),y
(#addr,d),z   direct page indirect z indexed        lda (#$12,d),z
[#addr,d]     direct page long indirect             lda [#$12,d]
[#addr,d],y   direct page long indirect y indexed   lda [#$12,d],y
#addr,k       program bank indexed                  jsr #0,k
(#addr,k,x)   program bank x indexed indirect       jmp (#$1234,k,x)
#addr,r       data stack indexed                    lda #1,r
(#addr,r),y   data stack indexed indirect y indexed lda (#$12,r),y
#addr,s       stack indexed                         lda #1,s
(#addr,s),y   stack indexed indirect y indexed      lda (#$12,s),y
addr,x        x indexed                             lda $12,x
addr,y        y indexed                             lda $12,y

Direct page, data bank, program bank indexed and long addressing modes of
instructions are intelligently chosen based on the instruction type, the
address ranges set up by .dpage, .databank and the current program counter
address. Therefore the `,d', `,b' and `,k' indexing is only used in very
special cases.

The immediate direct page indexed `#0,d' addressing mode is usable for direct
page access. The 8 bit constant is a direct offset from the start of actual
direct page. Alternatively it may be written as `0,d'.

The immediate data bank indexed `#0,b' addressing mode is usable for data bank
access. The 16 bit constant is a direct offset from the start of actual data
bank. Alternatively it may be written as `0,b'.

The immediate program bank indexed `#0,k' addressing mode is usable for program
bank jumps, branches and calls. The 16 bit constant is a direct offset from the
start of actual program bank. Alternatively it may be written as `0,k'.

The immediate stack indexed `#0,s' and data stack indexed `#0,r' accept 8 bit
constants as an offset from the start of (data) stack. These are sometimes
written without the immediate notation, but this makes it more clear what's
going on. For the same reason the move instructions are written with an
immediate addressing mode `#0,#0' as well.

The immediate (#) addressing mode expects unsigned values of byte or word size.
Therefore it only accepts constants of 1 byte or in range 0-255 or 2 bytes or
in range 0-65535.

The signed immediate (#+ and #-) addressing mode is to allow signed numbers to
be used as immediate constants. It accepts a single byte or an integer in range
-128-127, or two bytes or an integer of -32768-32767.

The use of signed immediate (like #-3) is seamless, but it needs to be
explicitly written out for variables or expressions (#+variable). In case the
unsigned variant is needed but the expression starts with a negation then it
needs to be put into parentheses (#(-variable)) or else it'll change the
address mode to signed.

Normally addressing mode operators are used in expressions right after
instructions. They can also be used for defining stack variable symbols when
using a 65816, or to force a specific addressing mode.

param   = #1,s            ;define a stack variable
const   = #1              ;immediate constant
        lda #0,b          ;always "absolute" lda $0000
        lda param         ;results in lda #$01,s
        lda param+1       ;results in lda #$02,s
        lda (param),y     ;results in lda (#$01,s),y
        ldx const         ;results in ldx #$01
        lda #-2           ;negative constant, $fe

Uninitialized memory

There's a special value for uninitialized memory, it's represented by a
question mark. Whenever it's used to generate data it creates a `hole' where
the previous content of memory is visible.

Uninitialized memory holes without previous content are not saved unless it's
really necessary for the output format, in that case it's replaced with zeros.

It's not just data generation statements (e.g. .byte) that can create
uninitialized memory, but .fill, .align or address manipulation as well.

*       = $200          ;bytes as necessary
        .word ?         ;2 bytes
        .fill 10        ;10 bytes
        .align 64       ;bytes as necessary

Booleans

There are two predefined boolean constant variables, true and false.

Booleans are created by comparison operators (<, <=, !=, ==, >=, >), logical
operators (&&, ||, ^^, !), the membership operator (in) and the all and any
functions.

Normally in numeric expressions true is 1 and false is 0, unless the `
-Wstrict-bool' command line option was used.

Other types can be converted to boolean by using the type bool.

         Boolean values of various types
bits  At least one non-zero bit
bool  When true
bytes At least one non-zero byte
code  Address is non-zero
float Not 0.0
int   Not zero
str   At least one non-zero byte after translation

Types

The various types mentioned earlier have predefined names. These can used for
conversions or type checks.

       Built-in type names
address Address type
bits    Bit string type
bool    Boolean type
bytes   Byte string type
code    Code type
dict    Dictionary type
float   Floating point type
gap     Uninitialized memory type
int     Integer type
list    List type
str     Character string type
tuple   Tuple type
type    Type type

        .cerror type(var) != str, "Not a string!"
        .text str(year)   ; convert to string

Symbols

Symbols are used to reference objects. Regularly named, anonymous and local
symbols are supported. These can be constant or re-definable.

Scopes are where symbols are stored and looked up. The global scope is always
defined and it can contain any number of nested scopes.

Symbols must be uniquely named in a scope, therefore in big programs it's hard
to come up with useful and easy to type names. That's why local and anonymous
symbols exists. And grouping certain related symbols into a scope makes sense
sometimes too.

Scopes are usually created by .proc and .block directives, but there are a few
other ways. Symbols in a scope can be accessed by using the dot operator, which
is applied between the name of the scope and the symbol (e.g.
myconsts.math.pi).

Regular symbols

Regular symbol names are starting with a letter and containing letters, numbers
and underscores. Unicode letters are allowed if the `-a' command line option
was used. There's no restriction on the length of symbol names.

Care must be taken to not use duplicate names in the same scope when the symbol
is used as a constant as there can be only one definition for them.

Duplicate names in parent scopes are not a problem and this gives the ability
to override names defined in lower scopes. However this can just as well lead
to mistakes if a lower scoped symbol with the same name was meant so there's a
-Wshadow command line option to warn if such ambiguity exists.

Case sensitivity can be enabled with the `-C' command line option, otherwise
all symbols are matched case insensitive.

For case insensitive matching it's possible to check for consistent symbol name
use with the `-Wcase-symbol' command line option.

A regular symbol is looked up first in the current scope, then in lower scopes
until the global scope is reached.

f       .block
g        .block
n        nop            ;jump here
         .bend
        .bend

        jsr f.g.n       ;reference from a scope
f.x     = 3             ;create x in scope f with value 3

Local symbols

Local symbols have their own scope between two regularly named code symbols and
are assigned to the code symbol above them.

Therefore they're easy to reuse without explicit scope declaration directives.

Not all regularly named symbols can be scope boundaries just plain code symbol
ones without anything or an opcode after them (no macros!). Symbols defined as
procedures, blocks, macros, functions, structures and unions are ignored. Also
symbols defined by .var, := or = don't apply, and there are a few more
exceptions, so stick to using plain code labels.

The name must start with an underscore (_), otherwise the same character
restrictions apply as for regular symbols. There's no restriction on the length
of the name.

Care must be taken to not use the duplicate names in the same scope when the
symbol is used as a constant.

A local symbol is only looked up in it's own scope and nowhere else.

incr    inc ac
        bne _skip
        inc ac+1
_skip   rts

decr    lda ac
        bne _skip
        dec ac+1
_skip   dec ac          ;symbol reused here
        jmp incr._skip  ;this works too, but is not advised

Anonymous symbols

Anonymous symbols don't have a unique name and are always called as a single
plus or minus sign. They are also called as forward (+) and backward (-)
references.

When referencing them `-' means the first backward, `--' means the second
backwards and so on. It's the same for forward, but with `+'. In expressions it
may be necessary to put them into brackets.

        ldy #4
-       ldx #0
-       txa
        cmp #3
        bcc +
        adc #44
+       sta $400,x
        inx
        bne -
        dey
        bne --

Excessive nesting or long distance references create poorly readable code. It's
also very easy to copy-paste a few lines of code with these references into a
code fragment already containing similar references. The result is usually a
long debugging session to find out what went wrong.

These references are also useful in segments, but this can create a nice trap
when segments are copied into the code with their internal references.

        bne +
        #somemakro      ;let's hope that this segment does
+       nop             ;not contain forward references...

Anonymous symbols are looked up first in the current scope, then in lower
scopes until the global scope is reached.

Anonymous labels within conditionally assembled code are counted even if the
code itself is not compiled and the label won't get defined. This ensures that
anonymous labels are always at the same "distance" independent of the
conditions in between.

Constant and re-definable symbols

Constant symbols can be created with the equal sign. These are not
re-definable. Forward referencing of them is allowed as they retain the objects
over compilation passes.

Symbols in front of code or certain assembler directives are created as
constant symbols too. They are bound to the object following them.

Re-definable symbols can be created by the .var directive or := construct.
These are also called as variables. They don't carry their content over from
the previous pass therefore it's not possible to use them before their
definition.

Variables can be conditionally defined using the :?= construct. If the variable
was defined already then the original value is retained otherwise a new one is
created with this value.

WIDTH   = 40            ;a constant
        lda #WIDTH      ;lda #$28
variabl .var 1          ;a variable
var2    := 1            ;another variable
variabl .var variabl + 1;update it verbosely
var2    += 1            ;compound assignment (add one)
var3    :?= 5           ;assign 5 if undefined

The star label

The `*' symbol denotes the current program counter value. When accessed it's
value is the program counter at the beginning of the line. Assigning to it
changes the program counter and the compiling offset.

Built-in functions

Built-in functions are pre-assigned to the symbols listed below. If you reuse
these symbols in a scope for other purposes then they become inaccessible, or
can perform a different function.

Built-in functions can be assigned to symbols (e.g. sinus = sin), and the new
name can be used as the original function. They can even be passed as
parameters to functions.

Mathematical functions

floor(<expression>)
    Round down. E.g. floor(-4.8) is -5.0
round(<expression>)
    Round to nearest away from zero. E.g. round(4.8) is 5.0
ceil(<expression>)
    Round up. E.g. ceil(1.1) is 2.0
trunc(<expression>)
    Round down towards zero. E.g. trunc(-1.9) is -1
frac(<expression>)
    Fractional part. E.g. frac(1.1) is 0.1
sqrt(<expression>)
    Square root. E.g. sqrt(16.0) is 4.0
cbrt(<expression>)
    Cube root. E.g. cbrt(27.0) is 3.0
log10(<expression>)
    Common logarithm. E.g. log10(100.0) is 2.0
log(<expression>)
    Natural logarithm. E.g. log(1) is 0.0
exp(<expression>)
    Exponential. E.g. exp(0) is 1.0
pow(<expression a>, <expression b>)
    A raised to power of B. E.g. pow(2.0, 3.0) is 8.0
sin(<expression>)
    Sine. E.g. sin(0.0) is 0.0
asin(<expression>)
    Arc sine. E.g. asin(0.0) is 0.0
sinh(<expression>)
    Hyperbolic sine. E.g. sinh(0.0) is 0.0
cos(<expression>)
    Cosine. E.g. cos(0.0) is 1.0
acos(<expression>)
    Arc cosine. E.g. acos(1.0) is 0.0
cosh(<expression>)
    Hyperbolic cosine. E.g. cosh(0.0) is 1.0
tan(<expression>)
    Tangent. E.g. tan(0.0) is 0.0
atan(<expression>)
    Arc tangent. E.g. atan(0.0) is 0.0
tanh(<expression>)
    Hyperbolic tangent. E.g. tanh(0.0) is 0.0
rad(<expression>)
    Degrees to radian. E.g. rad(0.0) is 0.0
deg(<expression>)
    Radian to degrees. E.g. deg(0.0) is 0.0
hypot(<expression y>, <expression x>)
    Polar distance. E.g. hypot(4.0, 3.0) is 5.0
atan2(<expression y>, <expression x>)
    Polar angle in -pi to +pi range. E.g. atan2(0.0, 3.0) is 0.0
abs(<expression>)
    Absolute value. E.g. abs(-1) is 1
sign(<expression>)
    Returns the sign of value as -1, 0 or 1 for negative, zero and positive.
    E.g. sign(-5) is -1

Other functions

all(<expression>)
    Return truth for various definitions of `all'.

                                 All function
    all bits set or no bits at all        all($f) is true
    all characters non-zero or empty      all("c") is true
    string
    all bytes non-zero or no bytes        all(x"ac24") is true
    all elements true or empty list       all([true, true, false]) is false

    Only booleans in a list are accepted with the `-Wstrict-bool' command line
    option.

any(<expression>)
    Return truth for various definitions of `any'.

                            Any function
    at least one bit set             any(~$f) is false
    at least one non-zero character  any("c") is true
    at least one non-zero byte       any(x"ac24") is true
    at least one true element        any([true, true, false]) is true

    Only booleans in a list are accepted with the `-Wstrict-bool' command line
    option.

binary(<string expression>[, <offset>[, <length>]])
    Returns the binary file content as bytes.

    This function reads the content of a binary file as a byte string. It also
    accepts optional offset and length parameters.

           Binary function invocation types
    Read everything        binary(name)
    Skip starting bytes    binary(name, offset)
    Some bytes from offset binary(name, offset, length)

    sidfile = "music.sid"        ; file name
    header  = binary(sidfile, $00, $7e)
    init    = header[$b:$9:-1]   ; init address (big endian)
    play    = header[$d:$b:-1]   ; play address (big endian)

    *       = header[$7c:$7e]    ; use loading address (little endian)
            .binary sidfile, $7e ; load music data

format(<string expression>[, <expression>, ...])
    Create string from values according to a format string.

    The format function converts a list of values into a character string. The
    converted values are inserted in place of the % sign. Optional conversion
    flags and minimum field length may follow, before the conversion type
    character. These flags can be used:

             Formatting flags
    #     alternate form ($a, %10, 10.)
    *     width/precision from list
    .     precision
    0     pad with zeros
    -     left adjusted (default right)
          blank when positive or minus sign
    +     sign even if positive

    The following conversion types are implemented:

          Formatting conversion types
    a A   hexadecimal floating point (uppercase)
    b     binary
    c     Unicode character
    d     decimal
    e E   exponential float (uppercase)
    f F   floating point (uppercase)
    g G   exponential/floating point
    s     string
    r     representation
    x X   hexadecimal (uppercase)
    %     percent sign

            .text format("%#04x bytes left", 1000); $03e8 bytes left

len(<expression>)
    Returns the number of elements.

                   Length of various types
    bit string       length in bits       len($034) is 12
    character string number of characters len("abc") is 3
    byte string      number of bytes      len(x"abcd23") is 3
    tuple, list      number of elements   len([1, 2, 3]) is 3
    dictionary       number of elements   len({1:2, 3:4]) is 2
    code             number of elements   len(label)

random([<expression>, ...])
    Returns a pseudo random number.

    The sequence does not change across compilations and is the same every
    time. Different sequences can be generated by seeding with .seed.

             Random function invocation types
    floating point number 0.0 <= x < 1.0   random()
    integer in range of 0 <= x < e         random(e)
    integer in range of s <= x < e         random(s, a)
    integer in range of s <= x < e, step t random(s, a, t)

            .seed 1234      ; default is boring, seed the generator
            .byte random(256); a pseudo random byte (0..255)
            .byte random([16] x 8); 8 pseudo random bytes (0..15)

range(<expression>[, <expression>, ...])
    Returns a list of integers in a range, with optional stepping.

                 Range function invocation types
    integers from 0 to e-1                         range(e)
    integers from s to e-1                         range(s, a)
    integers from s to e (not including e), step t range(s, a, t)

            .byte range(16) ; 0, 1, ..., 14, 15
            .char range(-5, 6); -5, -4, ..., 4, 5
    mylist  = range(10, 0, -2); [10, 8, 6, 4, 2]

repr(<expression>)
    Returns a string representation of value.

            .warn repr(var) ; pretty print value, for debugging

size(<expression>)
    Returns the size of code, structure or union in bytes.

            ldx #size(var) ; size to x

sort(<list>)
    Returns a sorted list or tuple.

    If the original list contains further lists then these must be all of the
    same length. In this case the order of lists is determined by comparing
    their elements from the start until a difference is found. The sort is
    stable.

    ; sort IRQ routines by their raster lines
    sorted  = sort([(60, irq1), (50, irq2)])
    lines   .byte sorted[:, 0] ; 50, 60
    irqs    .addr sorted[:, 1] ; irq2, irq1

Expressions

Operators

The following operators are available. Not all are defined for all types of
arguments and their meaning might slightly vary depending on the type.

            Unary operators
- negative             + positive
! not                  ~ invert
* convert to arguments ^ decimal string

The `^' decimal string operator will be changed to mean the bank byte soon.
Please update your sources to use format("%d", xxx) instead! This is done to be
in line with it's use in most other assemblers.

        Binary operators
+  add         -  subtract
*  multiply    /  divide
%  modulo      ** raise to power
|  binary or   ^  binary xor
&  binary and  << shift left
>> shift right .  member
.. concat      x  repeat
in contains

There's a ternary operator (? :) which gives the second value if the first is
true or the third if the first is false.

Parenthesis (( )) can be used to override operator precedence. Don't forget
that they also denote indirect addressing mode for certain opcodes.

        lda #(4+2)*3

Comparison operators

Traditional comparison operators give false or true depending on the result.

The compare operator (<=>) gives -1 for less, 0 for equal and 1 for more.

        Comparison operators
<=> compare
==  equals    != not equal
<   less than >= more than or equals
>   more than <= less than or equals

Bit string extraction operators

These unary operators extract 8 or 16 bits as a bit string from various types
of operands.

     Bit string extraction operators
<  lower byte              >  higher byte
<> lower word              >` higher word
>< lower byte swapped word `  bank byte

        lda #<label
        ldy #>label
        jsr $ab1e

        ldx #<>source   ; word extraction
        ldy #<>dest
        lda #size(source)-1
        mvn #`source, #`dest; bank extraction

Conditional operators

Boolean conditional operators give false or true or one of the operands as the
result.

              Logical and conditional operators
x || y      if x is true then x otherwise y
x ^^ y      if both false or true then false otherwise x || y
x && y      if x is true then y otherwise x
!x          if x is true then false otherwise true
c ? x : y   if c is true then x otherwise y
x <? y      if x is smaller then x otherwise y
x >? y      if x is greater then x otherwise y

;Silly example for 1=>"simple", 2=>"advanced", else "normal"
        .text MODE == 1 && "simple" || MODE == 2 && "advanced" || "normal"
        .text MODE == 1 ? "simple" : MODE == 2 ? "advanced" : "normal"
;Limit result to 0 .. 8
light   .byte 0 >? range(-16, 101)/6 <? 8

Please note that these are not short circuiting operations and both sides are
calculated even if thrown away later.

With the `-Wstrict-bool' command line option booleans are required as arguments
and only the `?' operator may return something else.

Address length forcing

Special addressing length forcing operators in front of an expression can be
used to make sure the expected addressing mode is used. Only applicable when
used directly with instructions.

           Address size forcing
@b          to force 8 bit address
@w          to force 16 bit address
@l          to force 24 bit address (65816)

        lda @w$0000

Compound assignment

These assignment operators are short hands for common .var directive use.

With the exception of := the variables updated must be defined beforehand. As
with .var they can't update constants, only variables.

       Compound assignments
+=  add         -=  subtract
*=  multiply    /=  divide
%=  modulo      **= raise to power
|=  binary or   ^=  binary xor
&=  binary and  ||= logical or
&&= logical and <<= shift left
>>= shift right ..= concat
<?= smaller     >?= greater
x=  repeat      .=  member

v       += 1            ; same as 'v .var v + 1'

Slicing and indexing

Lists, character strings, byte strings and bit strings support various slicing
and indexing possibilities through the [] operator.

Indexing elements with positive integers is zero based. Negative indexes are
transformed to positive by adding the number of elements to them, therefore -1
is the last element. Indexing with list of integers is possible as well so [1,
2, 3][(-1, 0, 1)] is [3, 1, 2].

Slicing is an operation when parts of sequence is extracted from a start
position to an end position with a step value. These parameters are separated
with colons enclosed in square brackets and are all optional. Their default
values are [start:maximum:step=1]. Negative start and end characters are
converted to positive internally by adding the length of string to them.
Negative step operates in reverse direction, non-single steps will jump over
elements.

This is quite powerful and therefore a few examples will be given here:

Positive indexing a[x]
    It'll simply extracts a numbered element. It is zero based, therefore
    "abcd"[1] results in "b".
Negative indexing a[-x]
    This extracts an element counted from the end, -1 is the last one. So
    "abcd"[-2] results in "c".
Cut off end a[:to]
    Extracts a continuous range stopping before `to'. So [10,20,30,40][:-1]
    results in [10,20,30].
Cut off start a[from:]
    Extracts a continuous range starting from `from'. So [10,20,30,40][-2:]
    results in [30,40].
Slicing a[from:to]
    Extracts a continuous range starting from element `from' and stopping
    before `to'. The two end positions can be positive or negative indexes. So
    [10,20,30,40][1:-1] results in [20,30].
Everything a[:]
    Giving no start or end will cover everything and therefore results in a
    complete copy.
Reverse a[::-1]
    This gives everything in reverse, so "abcd"[::-1] is "dcba".
Stepping through a[from:to:step]
    Extracts every `step'th element starting from `from' and stopping before
    `to'. So "abcdef"[1:4:2] results in "bd". The `from' and `to' can be
    omitted in case it starts from the beginning or end at the end. If the
    `step' is negative then it's done in reverse.
Extract multiple elements a[list]
    Extract elements based on a list. So "abcd"[[1,3]] will be "bd".

The fun start with nested lists and tuples, as these can be used to create a
matrix. The examples will be given for a two dimensional matrix for easier
understanding, but this also works in higher dimensions.

Extract row a[x]
    Given a [(1,2),(3,4)] matrix [0] will give the first row which is (1,2)
Extract row range a[from:to]
    Given a [(1,2),(3,4),(5,6),(7,8)] matrix [1:3] will give [(3,4),(5,6)]
Extract column a[x]
    Given a [(1,2),(3,4)] matrix [:,0] will give the first column of all rows
    which is [1,3]
Extract column range a[:,from:to]
    Given a [(1,2,3,4),(5,6,7,8)] matrix [:,1:3] will give [(2,3),(6,7)]

And it works for list of indexes, negative indexes, stepped ranges, reversing,
etc. on all axes in too many ways to show all possibilities.

Basically it's just the indexing and slicing applied on nested constructs,
where each nesting level is separated by a comma.

-------------------------------------------------------------------------------

Compiler directives

Controlling the compile offset and program counter

Two counters are used while assembling.

The compile offset is where the data and code ends up in memory (or in image
file).

The program counter is what labels get set to and what the special star label
refers to. It wraps when the border of a 64 KiB program bank is crossed. The
actual program bank is not incremented, just like on a real processor.

Normally both are the same (code is compiled to the location it runs from) but
it does not need to be.

*= <expression>
    The compile offset is adjusted so that the program counter will match the
    requested address in the expression.

    ;Offset PC       Bytes          Disassembly     Source
                                                    *       = $0800
    >0800                                                   .byte
                                                            .logical $1000
    >0800   1000                                            .byte
                                                    *       = $1200
    >0a00   1200                                            .byte
                                                            .here
    >0a00                                                   .byte

.offs <expression>
    Sets the compile offset relative to the program counter.

    Popular in old TASM code where this was the only way to create relocated
    code, otherwise it's use is not recommended as there are easier to use
    alternatives below.

    ;Offset PC       Bytes          Disassembly     Source
                                                    *       = $1000
    .1000           ea              nop                     nop
                                                            .offs 100
    .1065   1001    ea              nop                     nop

.logical <expression>
.here
    Changes the program counter only, the compile offset is not changed. When
    finished all continues where it was left off before.

    The naming is not logical at all for relocated code, but that's how it was
    named in old 6502tass.

    It's used for code copied to it's proper location at runtime. Can be nested
    of course.

    ;Offset PC       Bytes          Disassembly     Source
                                                    *       = $1000
                                                            .logical $300
    .1000   0300     a9 80          lda #$80        drive   lda #$80
    .1002   0302     85 00          sta $00                 sta $00
    .1004   0304     4c 00 03       jmp $0300               jmp drive
                                                            .here

.virtual [<expression>]
.endv
    Changes the program counter to the expression (if given) and discards the
    result of compilation.

    This is useful to define structures to fixed addresses.

            .virtual $d400  ; base address
    sid     .block
    freq    .word ?         ; frequency
    pulsew  .word ?         ; pulse width
    control .byte ?         ; control
    ad      .byte ?         ; attack/decay
    sr      .byte ?         ; sustain/release
            .bend
            .endv

    Or to define stack "allocated" variables on 65816.

            .virtual #1,s
    p1      .addr ?         ; at #1,s
    tmp     .byte ?         ; at #3,s
            .endv
            lda (p1),y      ; lda ($01,s),y

.align <expression>[, <fill>]
    Align the program counter to a dividable address by inserting uninitialized
    memory or repeated bytes.

    Usually used to page align data or code to avoid penalty cycles when
    indexing or branching.

    ;Offset PC       Bytes          Disassembly     Source
                                                    *       = $ffc
    >0ffc                                                   .align $100
    .1000            ee 19 d0       inc $d019       irq     inc $d019
    >1003            ea                                     .align 4, $ea
    .1004            69 01          adc #$01        loop    adc #1

    When alignment is done within named structures then it's relative to the
    start of the structure. This means the structure layout will be always the
    same independent which address it's instantiated at. Anonymous structures
    do not change the way the alignment works.

Dumping data

Storing numeric values

Multi byte numeric data is stored in the little-endian order, which is the
natural byte order for 65xx processors. Numeric ranges are enforced depending
on the directives used.

When using lists or tuples their content will be used one by one. Uninitialized
data (`?') creates holes of different sizes. Character string constants are
converted using the current encoding.

Please note that multi character strings usually don't fit into 8 bits and
therefore the .byte directive is not appropriate for them. Use .text instead
which accepts strings of any length.

.byte <expression>[, <expression>, ...]
    Create bytes from 8 bit unsigned constants (0-255)
.char <expression>[, <expression>, ...]
    Create bytes from 8 bit signed constants (-128-127)

    >1000  ff 03                             .byte 255, $03
    >1002  41                                .byte "a"
    >1003                                    .byte ?        ; reserve 1 byte
    >1004  fd                                .char -3
    ;Store 4.4 signed fixed point constants
    >1005  c8 34 32                          .char (-3.5, 3.25, 3.125) * 1p4
    ;Compact computed jumps using self modifying code
    .1008  bd 0f 10  lda $1010,x             lda jumps,x
    .100b  8d 0e 10  sta $100f               sta smod+1
    .100e  d0 fe     bne $100e       smod    bne *
    ;Routines nearby (-128-127 bytes)
    >1010  23 49                     jumps   .char (routine1, routine2)-smod-2

.word <expression>[, <expression>, ...]
    Create bytes from 16 bit unsigned constants (0-65535)
.sint <expression>[, <expression>, ...]
    Create bytes from 16 bit signed constants (-32768-32767)

    >1000  42 23 55 45                       .word $2342, $4555
    >1004                                    .word ?        ; reserve 2 bytes
    >1006  eb fd 51 11                       .sint -533, 4433
    ;Store 8.8 signed fixed point constants
    >100a  80 fc 40 03 20 03                 .sint (-3.5, 3.25, 3.125) * 1p8
    .1010  bd 19 10  lda $1019,x             lda texts,x
    .1013  bc 1a 10  ldy $101a,x             ldy texts+1,x
    .1016  4c 1e ab  jmp $ab1e               jmp $ab1e
    >1019  33 10 59 10               texts   .word text1, text2

.addr <expression>[, <expression>, ...]
    Create 16 bit address constants for addresses (in current program bank)
.rta <expression>[, <expression>, ...]
    Create 16 bit return address constants for addresses (in current program
    bank)

                                            *       = $12000
    .012000  7c 03 20       jmp ($012003,x)         jmp (jumps,x)
    >012003  50 20 32 03 92 15              jumps   .addr $12050, routine1, routine2
    ;Computed jumps by using stack (current bank)
                                            *       = $103000
    .103000  bf 0c 30 10    lda $10300c,x           lda rets+1,x
    .103004  48             pha                     pha
    .103005  bf 0b 30 10    lda $10300b,x           lda rets,x
    .103009  48             pha                     pha
    .10300a  60             rts                     rts
    >10300b  ff ef a1 36 f3 42              rets    .rta $10f000, routine1, routine2

.long <expression>[, <expression>, ...]
    Create bytes from 24 bit unsigned constants (0-16777215)
.lint <expression>[, <expression>, ...]
    Create bytes from 24 bit signed constants (-8388608-8388607)

    >1000  56 34 12                          .long $123456
    >1003                                    .long ?                ; reserve 3 bytes
    >1006  eb fd ff 51 11 00                 .lint -533, 4433
    ;Store 8.16 signed fixed point constants
    >100c  5d 8f fc 66 66 03 1e 85           .lint (-3.44, 3.4, 3.52) * 1p16
    >1014  03
    ;Computed long jumps with jump table (65816)
    .1015  bd 2a 10  lda $102a,x             lda jumps,x
    .1018  8d 11 03  sta $0311               sta ind
    .101b  bd 2b 10  lda $102b,x             lda jumps+1,x
    .101e  8d 12 03  sta $0312               sta ind+1
    .1021  bd 2c 10  lda $102c,x             lda jumps+2,x
    .1024  8d 13 03  sta $0313               sta ind+2
    .1027  dc 11 03  jmp [$0311]             jmp [ind]
    >102a  32 03 01 92 05 02         jumps   .long routine1, routine2

.dword <expression>[, <expression>, ...]
    Create bytes from 32 bit constants (0-4294967295)
.dint <expression>[, <expression>, ...]
    Create bytes from 32 bit signed constants (-2147483648-2147483647)

    >1000  78 56 34 12              .dword $12345678
    >1004                           .dword ?        ; reserve 4 bytes
    >1008  5d 7a 79 e7              .dint -411469219
    ;Store 16.16 signed fixed point constants
    >100c  5d 8f fc ff 66 66 03 00  .dint (-3.44, 3.4, 3.52) * 1p16
    >1014  1e 85 03 00

Storing string values

The following directives store strings of characters, bytes or bits as bytes.
Small numeric constants can be mixed in to represent single byte control
characters.

When using lists or tuples their content will be used one by one. Uninitialized
data (`?') creates byte sized holes. Character string constants are converted
using the current encoding.

.text <expression>[, <expression>, ...]
    Assemble strings into 8 bit bytes.

    >1000  4f 45 d5  .text "oeU"
    >1003  4f 45 d5  .text 'oeU'
    >1006  17 33     .text 23, $33  ; bytes
    >1008  0d 0a     .text $0a0d    ; $0d, $0a, little endian!
    >100a  1f        .text %00011111; more bytes

.fill <length>[, <fill>]
    Reserve space (using uninitialized data), or fill with repeated bytes.

    >1000            .fill $100      ;no fill, just reserve $100 bytes
    >1100  00 00 00  .fill $4000, 0  ;16384 bytes of 0
    ...
    >5100  55 aa 55  .fill 8000, [$55, $aa];8000 bytes of alternating $55, $aa
    ...
    >7040  ff ff ff  .fill $7100 - *, $ff;fill until $7100 with $ff
    ...

.shift <expression>[, <expression>, ...]
    Assemble strings of 7 bit bytes and mark the last byte by setting it's most
    significant bit.

    Any byte which already has the most significant bit set will cause an
    error. The last byte can't be uninitialized or missing of course.

    The naming comes from old TASM and is a reference to setting the high bit
    of alphabetic letters which results in it's uppercase version in PETSCII.

    .1000  a2 00          ldx #$00                ldx #0
    .1002  bd 10 10       lda $1010,x     loop    lda txt,x
    .1005  08             php                     php
    .1006  29 7f          and #$7f                and #$7f
    .1008  20 d2 ff       jsr $ffd2               jsr $ffd2
    .100b  e8             inx                     inx
    .100c  28             plp                     plp
    .100d  10 f3          bpl $1002               bpl loop
    .100f  60             rts                     rts
    >1010  53 49 4e 47 4c 45 20 53        txt     .shift "single", 32, "string"
    >1018  54 52 49 4e c7

.shiftl <expression>[, <expression>, ...]
    Assemble strings of 7 bit bytes shifted to the left once with the last
    byte's least significant bit set.

    Any byte which already has the most significant bit set will cause an error
    as this is cut off on shifting. The last byte can't be uninitialized or
    missing of course.

    The naming is a reference to left shifting.

    .1000  a2 00          ldx #$00                ldx #0
    .1002  bd 0d 10       lda $100d,x     loop    lda txt,x
    .1005  4a             lsr a                   lsr
    .1006  9d 00 04       sta $0400,x             sta $400,x      ;screen memory
    .1009  e8             inx                     inx
    .100a  90 f6          bcc $1002               bcc loop
    .100c  60             rts                     rts
                                                  .enc "screen"
    >100d  a6 92 9c 8e 98 8a 40 a6                .shiftl "single", 32, "string"
    >1015  a8 a4 92 9c 8f                 txt     .enc "none"

.null <expression>[, <expression>, ...]
    Same as .text, but adds a zero byte to the end. An existing zero byte is an
    error as it'd cause a false end marker.

    .1000  a9 07          lda #$07                lda #<txt
    .1002  a0 10          ldy #$10                ldy #>txt
    .1004  20 1e ab       jsr $ab1e               jsr $ab1e
    >1007  53 49 4e 47 4c 45 20 53        txt     .null "single", 32, "string"
    >100f  54 52 49 4e 47 00

.ptext <expression>[, <expression>, ...]
    Same as .text, but prepend the number of bytes in front of the string
    (pascal style string). Therefore it can't do more than 255 bytes.

    .1000  a9 1d          lda #$1d                lda #<txt
    .1002  a2 10          ldx #$10                ldx #>txt
    .1004  20 08 10       jsr $1008               jsr print
    .1007  60             rts                     rts

    .1008  85 fb          sta $fb         print   sta $fb
    .100a  86 fc          stx $fc                 stx $fc
    .100c  a0 00          ldy #$00                ldy #0
    .100e  b1 fb          lda ($fb),y             lda ($fb),y
    .1010  f0 0a          beq $101c               beq null
    .1012  aa             tax                     tax
    .1013  c8             iny             -       iny
    .1014  b1 fb          lda ($fb),y             lda ($fb),y
    .1016  20 d2 ff       jsr $ffd2               jsr $ffd2
    .1019  ca             dex                     dex
    .101a  d0 f7          bne $1013               bne -
    .101c  60             rts             null    rts
    >101d  0d 53 49 4e 47 4c 45 20        txt     .ptext "single", 32, "string"
    >1025  53 54 52 49 4e 47

Text encoding

64tass supports sources written in UTF-8, UTF-16 (be/le) and RAW 8 bit
encoding. To take advantage of this capability custom encodings can be defined
to map Unicode characters to 8 bit values in strings.

.enc "<name>"
    Selects text encoding, predefined encodings are `none' and `screen' (screen
    code), anything else is user defined. All user encodings start without any
    character or escape definitions, add some as required.

                                    .enc "screen";screen code mode
    >1000  13 03 12 05 05 0e 20 03  .text "screen codes"
    >1008  0f 04 05 13
    .100c  c9 15     cmp #$15       cmp #"u"    ;compare screen code
                                    .enc "none" ;normal mode again
    .100e  c9 55     cmp #$55       cmp #"u"    ;compare PETSCII

.cdef <start>, <end>, <coded> [, <start>, <end>, <coded>, ...]
.cdef "<start><end>", <coded> [, "<start><end>", <coded>, ...]
    Assigns characters in a range to single bytes.

    This is a simple single character to byte translation definition. It is
    applied to a range as characters and bytes are usually assigned
    sequentially. The start and end positions are Unicode character codes
    either by numbers or by typing them. Overlapping ranges are not allowed.

            .enc "ascii"    ;define an ascii encoding
            .cdef " ~", 32  ;identity for printable

.edef "<escapetext>", <value> [, "<escapetext>", <value>, ...]
    Assigns strings to byte sequences as a translated value.

    When these substrings are found in a text they are replaced by bytes
    defined here. When strings with common prefixes are used the longest match
    wins. Useful for defining non-typeable control code aliases, or as a simple
    tokenizer.

        .enc "petscii"  ;define an ascii->petscii encoding
        .cdef " @", 32  ;characters
        .cdef "AZ", $c1
        .cdef "az", $41
        .cdef "[[", $5b
        .cdef "??", $5c
        .cdef "]]", $5d
        .cdef "??", $5e
        .cdef $2190, $2190, $1f;left arrow

        .edef "\n", 13  ;one byte control codes
        .edef "{clr}", 147
        .edef "{crlf}", [13, 10];two byte control code
        .edef "<nothing>", [];replace with no bytes

>1000  93 d4 45 58 54 20 49 4e     .text "{clr}Text in PETSCII\n"
>1008  20 d0 c5 d4 d3 c3 c9 c9 0d

Structured data

Structures and unions can be defined to create complex data types. The offset
of fields are available by using the definition's name. The fields themselves
by using the instance name.

The initialization method is very similar to macro parameters, the difference
is that unset parameters always return uninitialized data (`?') instead of an
error.

Structure

Structures are for organizing sequential data, so the length of a structure is
the sum of lengths of all items.

.struct [<name>][=<default>]][, [<name>][=<default>] ...]
.ends [<result>][, <result> ...]
    Structure definition, with named parameters and default values
.dstruct <name>[, <initialization values>]
.<name> [<initialization values>]
    Create instance of structure with initialization values

        .struct         ;anonymous structure
x       .byte 0         ;labels are visible
y       .byte 0         ;content compiled here
        .ends           ;useful inside unions

nn_s    .struct col, row;named structure
x       .byte \col      ;labels are not visible
y       .byte \row      ;no content is compiled here
        .ends           ;it's just a definition

nn      .dstruct nn_s, 1, 2;structure instance, content here

        lda nn.x        ;direct field access
        ldy #nn_s.x     ;get offset of field
        lda nn,y        ;and use it indirectly

Union

Unions can be used for overlapping data as the compile offset and program
counter remains the same on each line. Therefore the length of a union is the
length of it's longest item.

.union [<name>][=<default>]][, [<name>][=<default>] ...]
.endu
    Union definition, with named parameters and default values
.dunion <name>[, <initialization values>]
.<name> [<initialization values>]
    Create instance of union with initialization values

        .union          ;anonymous union
x       .byte 0         ;labels are visible
y       .word 0         ;content compiled here
        .endu

nn_u    .union          ;named union
x       .byte ?         ;labels are not visible
y       .word \1        ;no content is compiled here
        .endu           ;it's just a definition

nn      .dunion nn_u, 1 ;union instance here

        lda nn.x        ;direct field access
        ldy #nn_u.x     ;get offset of field
        lda nn,y        ;and use it indirectly

Combined use of structures and unions

The example below shows how to define structure to a binary include.

        .union
        .binary "pic.drp", 2
        .struct
color   .fill 1024
screen  .fill 1024
bitmap  .fill 8000
backg   .byte ?
        .ends
        .endu

Anonymous structures and unions in combination with sections are useful for
overlapping memory assignment. The example below shares zero page allocations
for two separate parts of a bigger program. The common subroutine variables are
assigned after in the `zp' section.

*       = $02
        .union          ;spare some memory
         .struct
          .dsection zp1 ;declare zp1 section
         .ends
         .struct
          .dsection zp2 ;declare zp2 section
         .ends
        .endu
        .dsection zp    ;declare zp section

Macros

Macros can be used to reduce typing of frequently used source lines. Each
invocation is a copy of the macro's content with parameter references replaced
by the parameter texts.

.segment [<name>][=<default>]][, [<name>][=<default>] ...]
.endm [<result>][, <result> ...]
    Copies the code segment as it is, so symbols can be used from outside, but
    this also means multiple use will result in double defines unless anonymous
    labels are used.
.macro [<name>][=<default>]][, [<name>][=<default>] ...]
.endm [<result>][, <result> ...]
    The code is enclosed in it's own block so symbols inside are
    non-accessible, unless a label is prefixed at the place of use, then local
    labels can be accessed through that label.
#<name> [<param>][[,][<param>] ...]
.<name> [<param>][[,][<param>] ...]
    Invoke the macro after `#' or `.' with the parameters. Normally the name of
    the macro is used, but it can be any expression.

;A simple macro
copy    .macro
        ldx #size(\1)
lp      lda \1,x
        sta \2,x
        dex
        bpl lp
        .endm

        #copy label, $500

;Use macro as an assembler directive
lohi    .macro
lo      .byte <(\@)
hi      .byte >(\@)
        .endm

var     .lohi 1234, 5678

        lda var.lo,y
        ldx var.hi,y

Parameter references

The first 9 parameters can be referenced by `\1'-`\9'. The entire parameter
list including separators is `\@'.

name    .macro
        lda #\1         ;first parameter 23+1
        .endm

        #name 23+1      ;call macro

Parameters can be named, and it's possible to set a default value after an
equal sign which is used as a replacement when the parameter is missing.

These named parameters can be referenced by \name or \{name}. Names must match
completely, if unsure use the quoted name reference syntax.

name    .macro first, b=2, , last
        lda #\first     ;first parameter
        lda #\b         ;second parameter
        lda #\3         ;third parameter
        lda #\last      ;fourth parameter
        .endm

        #name 1, , 3, 4 ;call macro

Text references

In the original turbo assembler normal references are passed by value and can
only appear in place of one. Text references on the other hand can appear
everywhere and will work in place of e.g. quoted text or opcodes and labels.
The first 9 parameters can be referenced as text by @1-@9.

name    .macro
        jsr print
        .null "Hello @1!";first parameter
        .endm

        #name "wth?"    ;call macro

Custom functions

Beyond the built-in functions mentioned earlier it's possible to define custom
ones for frequently used calculations.

.function <name>[=<default>]][, <name>[=<default>] ...][, *<name>]
.endf [<result>][, <result> ...]
    Defines a user function
#<name> [<param>][[,][<param>] ...]
.<name> [<param>][[,][<param>] ...]
<name> [<param>][[,][<param>] ...]
    Invoke a function like a macro, directive or pseudo instruction.

Parameters are assigned to variables in the function scope on invocation. The
default values are calculated at function definition time only, and these
values are used at invocation time when a parameter is missing.

Extra parameters are not accepted, unless the last parameter symbol is preceded
with a star, in this case these parameters are collected into a tuple. Multiple
values are returned are also returned as tuple.

Functions can span multiple lines but unlike macros they can't create new code.
Only those external variables and functions are available which were accessible
at the place of definition, but not those at the place of invocation.

wpack   .function a, b=0
        .endf a+b*256

        .word wpack(1), wpack(2, 3)

If a function is used as macro, directive or pseudo instruction and there's a
label in front then the returned value is assigned to it. If nothing is
returned then it's used as regular label. Of course when used like this it can
create code and access local variables.

mva     .function s, d
        lda s
        sta d
        .endf

        mva #1, label

Conditional assembly

To prevent parts of source from compiling conditional constructs can be used.
This is useful when multiple slightly different versions needs to be compiled
from the same source.

Anonymous labels are still recognized in the non-compiling parts even if they
won't get defined. This ensures consistent relative referencing across
conditionally compiled areas with such labels.

If, else if, else

.if <condition>
    Compile if condition is true
.elsif <condition>
    Compile if previous conditions were not met and the condition is true
.else
    Compile if previous conditions were not met
.fi
.endif
    End of conditional compilation.
.ifne <value>
    Compile if value is not zero
.ifeq <value>
    Compile if value is zero
.ifpl <value>
    Compile if value is greater or equal zero
.ifmi <value>
    Compile if value is less than zero

The .ifne, .ifeq, .ifpl and .ifmi directives exists for compatibility only, in
practice it's better to use comparison operators instead.

        .if wait==2     ;2 cycles
        nop
        .elsif wait==3  ;3 cycles
        bit $ea
        .elsif wait==4  ;4 cycles
        bit $eaea
        .else           ;else 5 cycles
        inc $2
        .fi

Switch, case, default

Similar to the .if/.elsif/.else/.fi construct, but the compared value needs to
be written only once in the switch statement.

.switch <expression>
    Evaluate expression and remember it
.case <expression>[, <expression> ...]
    Compile if the previous conditions were all skipped and one of the values
    equals
.default
    Compile if the previous conditions were all skipped
.endswitch
    End of conditional compilation.

        .switch wait
        .case 2         ;2 cycles
        nop
        .case 3         ;3 cycles
        bit $ea
        .case 4         ;4 cycles
        bit $eaea
        .default        ;else 5 cycles
        inc $2
        .endswitch

Comment

.comment
    Never compile.
.endc
    End of conditional compilation.

        .comment
        lda #1          ;this won't be compiled
        sta $d020
        .endc

Repetitions

The following directives are used to repeat code or data.

The regular non-scoped variants cover most cases except when normal labels are
required as those will be double defined.

Scoped variants (those starting with the letter b) create a new scope for each
iteration. This allows normal labels without collision but it's a bit more
resource intensive.

If the scoped variant is prefixed with a label then the list of individual
scopes for each iteration will be assigned to it. This allows accessing labels
within.

.for [<assignment>], [<condition>], [<assignment>]
.bfor [<assignment>], [<condition>], [<assignment>]
.next
    Assign initial value, loop while the condition is true and modify value.

    First a variable is set, usually this is used for counting. This is
    optional, the variable may be set already before the loop.

    Then the condition is checked and the enclosed lines are compiled if it's
    true. If there's no condition then it's an infinite loop and .break must be
    used to terminate it.

    After an iteration the second assignment is calculated, usually it's
    updating the loop counter variable. This is optional as well.

            ldx #0
            lda #32
    lp      .for ue := $400, ue < $800, ue += $100
            sta ue,x         ;do $400, $500, $600 and $700
            .next
            dex
            bne lp

.for <variable>[, <variable>, ...] in <expression>
.bfor <variable>[, <variable>, ...] in <expression>
.next
    Assign variable(s) to values in sequence one-by-one in order.

    The expression is usually the range function or some sort of list.

            .for col in 0, 11, 12, 15, 1
            lda #col         ;0, 11, 12, 15 and 1
            sta $d020
            .next

.rept <expression>
.brept <expression>
.next
    Repeat enclosed lines the specified number of times.

            .rept 100
    -       inx
            bne -
            .next

    lst     .brept 100       ;each iteration into a tuple
    label   jmp label        ;not a duplicate definition
            .next
            jmp lst[5].label ;use label of 6th iteration

.while <condition>
.bwhile <condition>
.next
    Repeat enclosed lines until the condition holds.

    Works as expected however the scoped variant might be tricky to use as
    variables in the condition might not be in the same scope as the loop body.

.break
    Exit current repetition loop immediately.
.breakif <condition>
    Exit current repetition loop immediately if the condition holds.

    It's a shorthand for a .if .break .fi sequence.

.continue
    Continue current repetition loop's next iteration.
.continueif <condition>
    Continue current repetition loop's next iteration if the condition holds.

    It's a shorthand for a .if .continue .fi sequence.

.next
    Closing directive of .for, .bfor, .rept, .brept, .while and .bwhile loop.
.lbl
    Creates a special jump label that can be referenced by .goto
.goto <labelname>
    Causes assembler to continue assembling from the jump label. No forward
    references of course, handle with care. Should only be used in classic TASM
    sources for creating loops.

    i       .var 100
    loop    .lbl
            nop
    i       .var i - 1
            .ifne i
            .goto loop       ;generates 100 nops
            .fi              ;the hard way ;)

Including files

Longer sources are usually separated into multiple files for easier handling.
Precomputed binary data can also be included directly without converting it
into source code first.

Search path is relative to the location of current source file. If it's not
found there the include search path is consulted for further possible
locations.

To make your sources portable please always use forward slashes (/) as a
directory separator and use lower/uppercase consistently in file names!

.include <filename>
    Include source file here.
.binclude <filename>
    Include source file here in it's local block. If the directive is prefixed
    with a label then all labels are local and are accessible through that
    label only, otherwise not reachable at all.


            .include "macros.asm"       ;include macros
    menu    .binclude "menu.asm"        ;include in a block
            jmp menu.start

.binary <filename>[, <offset>[, <length>]]
    Include raw binary data from file.

    By using offset and length it's possible to break out chunks of data from a
    file separately, like bitmap and colors for example. Negative offsets are
    calculated from the end of file.

            .binary "stuffz.bin"        ;simple include, all bytes
            .binary "stuffz.bin", 2     ;skip start address
            .binary "stuffz.bin", 2, 1000;skip start address, 1000 bytes max

Scopes

Scopes may contain symbols or other scopes nested. They are useful to avoid
symbol clashes as the same symbol name can repeated as long as it's in a
different scope.

In nested scopes the symbol lookup starts from the local scope and goes in the
direction of the global scope. This means that local variables will `shadow'
global one with the same name.

.proc
.pend
    Procedure start and end of procedure.

    If it's label is not used then the code won't be compiled at all. This is
    very useful to avoid a lot of .if blocks to exclude unused sections of
    code.

    All labels inside are local enclosed in a scope and are accessible through
    the prefixed label. Useful for building libraries.

    ize     .proc
            nop
    cucc    nop
            .pend

            jsr ize
            jmp ize.cucc

.block
.bend
    Block start and block end.

    All labels inside a block are local enclosed in a scope. If prefixed with a
    label local variables are accessible through that label using the dot
    notation, otherwise not at all.

            .block
            inc count + 1
    count   ldx #0
            .bend

.namespace [<symbol>]
.endn
    Namespace area

    This directive either creates a new scope (if used without a parameter) or
    activates the one in the parameter.

    The scope can be assigned to a symbol in front of the directive so that it
    can be reactivated later.

    This enabled label definitions into the same scope in different files.

.weak
.endweak
    Weak symbol area

    Any symbols defined inside can be overridden by `stronger' symbols in the
    same scope from outside. Can be nested as necessary.

    This gives the possibility of giving default values for symbols which might
    not always exist without resorting to .ifdef/.ifndef or similar directives
    in other assemblers.

    symbol  = 1            ;stronger symbol than the one below
            .weak
    symbol  = 0            ;default value if the one above does not exists
            .endweak
            .if symbol     ;almost like an .ifdef ;)

    Other use of weak symbols might be in included libraries to change default
    values or replace stub functions and data structures.

    If these stubs are defined using .proc/.pend then their default
    implementations will not even exists in the output at all when a stronger
    symbol overrides them.

    Multiple definition of a symbol with the same `strength' in the same scope
    is of course not allowed and it results in double definition error.

    Please note that .ifdef/.ifndef directives are left out from 64tass for of
    technical reasons, so don't wait for them to appear anytime soon.

.with <symbol>
.endwith
    Namespace access

    This directive is similar to .namespace but it gives access to another
    scope's variables without leaving the current scope. May be useful to allow
    a short hand access in some situations.

    It's advised to use the -Wshadow command line option to warn about any
    unexpected symbol ambiguity.

Sections

Sections can be used to collect data or code into separate memory areas without
moving source code lines around. This is achieved by having separate compile
offset and program counters for each defined section.

.section <name>
.send [<name>]
    Defines a section fragment. The name at .send must match but it's optional.
.dsection <name>
    Collect the section fragments here.

All .section fragments are compiled to the memory area allocated by the
.dsection directive. Compilation happens as the code appears, this directive
only assigns enough space to hold all the content in the section fragments.

The space used by section fragments is calculated from the difference of
starting compile offset and the maximum compile offset reached. It is possible
to manipulate the compile offset in fragments, but putting code before the
start of .dsection is not allowed.

*       = $02
        .dsection zp   ;declare zero page section
        .cerror * > $30, "Too many zero page variables"

*       = $334
        .dsection bss   ;declare uninitialized variable section
        .cerror * > $400, "Too many variables"

*       = $0801
        .dsection code   ;declare code section
        .cerror * > $1000, "Program too long!"

*       = $1000
        .dsection data   ;declare data section
        .cerror * > $2000, "Data too long!"
;--------------------
        .section code
        .word ss, 2005
        .null $9e, format("%d", start)
ss      .word 0

start   sei
        .section zp     ;declare some new zero page variables
p2      .addr ?         ;a pointer
        .send zp
        .section bss    ;new variables
buffer  .fill 10        ;temporary area
        .send bss

        lda (p2),y
        lda #<label
        ldy #>label
        jsr print

        .section data   ;some data
label   .null "message"
        .send data

        jmp error
        .section zp     ;declare some more zero page variables
p3      .addr ?         ;a pointer
        .send zp
        .send code

The compiled code will look like:

>0801    0b 08 d5 07                            .word ss, 2005
>0805    9e 32 30 36 31 00                      .null $9e, format("%d", start)
>080b    00 00                          ss      .word 0

.080d    78                             start   sei

>0002                                   p2      .addr ?         ;a pointer
>0334                                   buffer  .fill 10        ;temporary area

.080e    b1 02                                  lda (p2),y
.0810    a9 00                                  lda #<label
.0812    a0 10                                  ldy #>label
.0814    20 1e ab                               jsr print

>1000    6d 65 73 73 61 67 65 00        label   .null "message"

.0817    4c e2 fc                               jmp error

>0004                                   p2      .addr ?         ;a pointer

Sections can form a hierarchy by nesting a .dsection into another section. The
section names must only be unique within a section but can be reused otherwise.
Parent section names are visible for children, siblings can be reached through
parents.

In the following example the included sources don't have to know which `code'
and `data' sections they use, while the `bss' section is shared for all banks.

;First 8K bank at the beginning, PC at $8000
*       = $0000
        .logical $8000
        .dsection bank1
        .cerror * > $a000, "Bank1 too long"
        .here

bank1   .block          ;Make all symbols local
        .section bank1
        .dsection code  ;Code and data sections in bank1
        .dsection data
        .section code   ;Pre-open code section
        .include "code.asm"; see below
        .include "iter.asm"
        .send code
        .send bank1
        .bend

;Second 8K bank at $2000, PC at $8000
*       = $2000
        .logical $8000
        .dsection bank2
        .cerror * > $a000, "Bank2 too long"
        .here

bank2   .block          ;Make all symbols local
        .section bank2
        .dsection code  ;Code and data sections in bank2
        .dsection data
        .section code   ;Pre-open code section
        .include "scr.asm"
        .send code
        .send bank2
        .bend

;Common data, avoid initialized variables here!
*       = $c000
        .dsection bss
        .cerror * > $d000, "Too much common data"
;------------- The following is in "code.asm"
code    sei

        .section bss   ;Common data section
buffer  .fill 10
        .send bss

        .section data  ;Data section (in bank1)
routine .addr print
        .send bss

65816 related

.as
.al
    Select short (8 bit) or long (16 bit) accumulator immediate constants.

            .al
            lda #$4322

.xs
.xl
    Select short (8 bit) or long (16 bit) index register immediate constants.

            .xl
            ldx #$1000

.autsiz
.mansiz
    Select automatic adjustment of immediate constant sizes based on SEP/REP
    instructions.

            .autsiz
            rep #$10        ;implicit .xl
            ldx #$1000

.databank <expression>
    Data bank (absolute) addressing is only used for addresses falling into
    this 64 KiB bank. The default is 0, which means addresses in bank zero.

    When data bank is switched off only data bank indexed (,b) addresses create
    data bank accessing instructions.

            .databank $10   ;data bank at $10xxxx
            lda $101234     ;results in $ad, $34, $12
            .databank ?     ;no data bank
            lda $1234       ;direct page or long addressing
            lda #$1234,b    ;results in $ad, $34, $12

.dpage <expression>
    Direct (zero) page addressing is only used for addresses falling into a
    specific 256 byte address range. The default is 0, which is the first page
    of bank zero.

    When direct page is switched off only the direct page indexed (,d)
    addresses create direct page accessing instructions.

            .dpage $400     ;direct page $400-$4ff
            lda $456        ;results in $a5, $56
            .dpage ?        ;no direct page
            lda $56         ;data bank or long addressing
            lda #$56,d      ;results in $a5, $56

Controlling errors

.page
.endp
    Gives an error on page boundary crossing, e.g. for timing sensitive code.

            .page
    table   .byte 0, 1, 2, 3, 4, 5, 6, 7
            .endp

.option allow_branch_across_page
    Switches error generation on page boundary crossing during relative branch.
    Such a condition on 6502 adds 1 extra cycle to the execution time, which
    can ruin the timing of a carefully cycle counted code.

            .option allow_branch_across_page = 0
            ldx #3          ;now this will execute in
    -       dex             ;16 cycles for sure
            bne -
            .option allow_branch_across_page = 1

.error <message> [, <message>, ...]
.cerror <condition>, <message> [, <message>, ...]
    Exit with error or conditionally exit with error

            .error "Unfinished here..."
            .cerror * > $1200, "Program too long by ", * - $1200, " bytes"

.warn <message> [, <message>, ...]
.cwarn <condition>, <message> [, <message>, ...]
    Display a warning message always or depending on a condition

            .warn "FIXME: handle negative values too!"
            .cwarn * > $1200, "This may not work!"

Target

.cpu <expression>
    Selects CPU according to the string argument.

            .cpu "6502"     ;standard 65xx
            .cpu "65c02"    ;CMOS 65C02
            .cpu "65ce02"   ;CSG 65CE02
            .cpu "6502i"    ;NMOS 65xx
            .cpu "65816"    ;W65C816
            .cpu "65dtv02"  ;65dtv02
            .cpu "65el02"   ;65el02
            .cpu "r65c02"   ;R65C02
            .cpu "w65c02"   ;W65C02
            .cpu "4510"     ;CSG 4510
            .cpu "default"  ;cpu set on commandline

Misc

.end
    Terminate assembly. Any content after this directive is ignored.
.eor <expression>
    XOR output with a 8 bit value. Useful for reverse screen code text for
    example, or for silly `encryption'.
.seed <expression>
    Seed the pseudo random number generator with an unsigned integer of maximum
    128 bits to make the generated numbers less boring.
.var <expression>
    Defines a variable identified by the label preceding, which is set to the
    value of expression or reference of variable.
.assert
.check
    Do not use these, the syntax will change in next version!

Printer control

.pron
.proff
    Turn on or off source listing on part of the file.

            .proff           ;Don't put filler bytes into listing
    *       = $8000
            .fill $2000, $ff ;Pre-fill ROM area
            .pron
    *       = $8000
            .addr reset, restore
            .text "CBM80"
    reset   cld

.hidemac
.showmac
    Ignored for compatibility.

-------------------------------------------------------------------------------

Pseudo instructions

Aliases

For better code readability BCC has an alias named BLT (Branch Less Than) and
BCS one named BGE (Branch Greater Equal).

        cmp #3
        blt exit        ; less than 3?

For similar reasons ASL has an alias named SHL (SHift Left) and LSR one named
SHR (SHift Right). This naming however is not very common.

The implied variants LSR, ROR, ASL and ROL are a shorthand for LSR A, ROR A,
ASL A and ROL A. Using the implied form is considered poor coding style.

For compatibility INA and DEA is a shorthand of INC A and DEC A. Therefore
there's no `implied' variants like INC or DEC. The full form with the
accumulator is preferred.

The longer forms of INC X, DEC X, INC Y, DEC Y, INC Z and DEC Z are available
for INX, DEX, INY, DEY, INZ and DEZ. For this to work care must be taken to not
reuse the `x', `y' and `z' single letter register symbols for other purposes.
Same goes for `a' of course.

Load instructions with registers are translated to transfer instructions. For
example LDA X becomes TXA.

Store instructions with registers are translated to transfer instructions, but
only if it involves the `s' or `b' registers. For example STX S becomes TXS.

Many illegal opcodes have aliases for compatibility as there's no standard
naming convention.

Always taken branches

For writing short code there are some special pseudo instructions for always
taken branches. These are automatically compiled as relative branches when the
jump distance is short enough and as JMP or BRL when longer.

The names are derived from conditional branches and are: GEQ, GNE, GCC, GCS,
GPL, GMI, GVC, GVS, GLT and GGE.

.0000    a9 03          lda #$03        in1     lda #3
.0002    d0 02          bne $0006               gne at          ;branch always
.0004    a9 02          lda #$02        in2     lda #2
.0006    4c 00 10       jmp $1000       at      gne $1000       ;branch further

If the branch would skip only one byte then the opposite condition is compiled
and only the first byte is emitted. This is now a never executed jump, and the
relative distance byte after the opcode is the jumped over byte. If the CPU has
long conditional branches (65CE02/4510) then the same method is applied to two
byte skips as well.

There's a pseudo opcode called GRA for CPUs supporting BRA, which is expanded
to BRL (if available) or JMP. A one byte skip will be shortened to a single
byte if the CPU has a NOP immediate instruction (R65C02/W65C02).

If the branch would not skip anything at all then no code is generated.

.0009                                           geq in3         ;zero length "branch"
.0009    18             clc             in3     clc
.000a    b0             bcs                     gcc at2         ;one byte skip, as bcs
.000b    38             sec             in4     sec             ;sec is skipped!
.000c    20 0f 00       jsr $000f       at2     jsr func
.000f                                   func

Please note that expressions like Gxx *+2 or Gxx *+3 are not allowed as the
compiler can't figure out if it has to create no code at all, the 1 byte
variant or the 2 byte one. Therefore use normal or anonymous labels defined
after the jump instruction when jumping forward!

Long branches

To avoid branch too long errors the assembler also supports long branches. It
can automatically convert conditional relative branches to it's opposite and a
JMP or BRL. This can be enabled on the command line using the `--long-branch'
option.

.0000    ea             nop                     nop
.0001    b0 03          bcs $0006               bcc $1000      ;long branch (6502)
.0003    4c 00 10       jmp $1000
.0006    1f 17 03       bbr 1,$17,$000c         bbs 1,23,$1000 ;long branch (R65C02)
.0009    4c 00 10       jmp $1000
.000c    d0 04          bne $0012               beq $10000     ;long branch (65816)
.000e    5c 00 00 01    jmp $010000
.0012    30 03          bmi $0017               bpl $1000      ;long branch (65816)
.0014    82 e9 lf       brl $1000
.0017    ea             nop                     nop

Please note that forward jump expressions like Bxx *+130, Bxx *+131 and Bxx
*+132 are not allowed as the compiler can't decide between a short/long branch.
Of course these destinations can be used, but only with normal or anonymous
labels defined after the jump instruction.

In the above example extra JMP instructions are emitted for each long branch.
This is suboptimal and wasting space if there are several long branches to the
same location in close proximity. Therefore the assembler might decide to reuse
a JMP for more than one long branch to save space.

-------------------------------------------------------------------------------

Original turbo assembler compatibility

How to convert source code for use with 64tass

Currently there are two options, either use `TMPview' by Style to convert the
source file directly, or do the following:

  * load turbo assembler, start (by SYS 9*4096 or SYS 8*4096 depending on
    version)
  * <- then l to load a source file
  * <- then w to write a source file in PETSCII format
  * convert the result to ASCII using petcat (from the vice package)

The resulting file should then (with the restrictions below) assemble using the
following command line:

64tass -C -T -a -W -i source.asm -o outfile.prg

Differences to the original turbo ass macro on the C64

64tass is nearly 100% compatible with the original `Turbo Assembler', and
supports most of the features of the original `Turbo Assembler Macro'. The
remaining notable differences are listed here.

Labels

The original turbo assembler uses case sensitive labels, use the `
--case-sensitive' command line option to enable this behaviour.

Expression evaluation

There are a few differences which can be worked around by the `
--tasm-compatible' command line option. These are:

The original expression parser has no operator precedence, but 64tass has. That
means that you will have to fix expressions using braces accordingly, for
example 1+2*3 becomes (1+2)*3.

The following operators used by the original Turbo Assembler are different:

       TASM Operator differences
.           bitwise or, now |
:           bitwise eor, now ^
!           force 16 bit address, now @w

The default expression evaluation is not limited to 16 bit unsigned numbers
anymore.

Macros

Macro parameters are referenced by `\1'-`\9' instead of using the pound sign.

Parameters are always copied as text into the macro and not passed by value as
the original turbo assembler does, which sometimes may lead to unexpected
behaviour. You may need to make use of braces around arguments and/or
references to fix this.

Bugs

Some versions of the original turbo assembler had bugs that are not reproduced
by 64tass, you will have to fix the code instead.

In some versions labels used in the first .block are globally available. If you
get a related error move the respective label out of the .block.

-------------------------------------------------------------------------------

Command line options

Short command line options consist of `-' and a letter, long options start with
`--'.

If `--' is encountered then further options are not recognized and are assumed
to be file names.

Options requiring file names are marked with `<filename>'. A single `-' as name
means standard input or output. File name quoting is system specific.

Output options

-o <filename>, --output <filename>
    Place output into <filename>. The default output filename is `a.out'. This
    option changes it.

    64tass a.asm -o a.prg

    This option may be used multiple times to output different sections in
    different formats of a single compilation.

    For multiple outputs the format options and output section selection must
    be placed before this option. The format selection will be unchanged if no
    new selection was made but the output section selection must be repeated
    for each output. The maximum image size will be the smallest of all
    selected formats. Using the same name multiple times is not a good idea.

--output-section <sectionname>
    By default all sections go into the output file. Using this option limits
    the output to specific section and it's children. This is useful to split a
    larger program into several files.

    64tass a.asm --output-section main -o main.prg
    64tass a.asm --output-section loader -o loader.prg

-X, --long-address
    Use 3 byte address/length for CBM and nonlinear output instead of 2 bytes.
    Also increases the size of raw output to 16 MiB.

    64tass --long-address --m65816 a.asm

--cbm-prg
    Generate CBM format binaries (default)

    The first 2 bytes are the little endian address of the first valid byte
    (start address). Overlapping blocks are flattened and uninitialized memory
    is filled up with zeros. Uninitialized memory before the first and after
    the last valid bytes are not saved. Up to 64 KiB or 16 MiB with long
    address.

    Used for C64 binaries.

-b, --nostart
    Output raw data without start address.

    Overlapping blocks are flattened and uninitialized memory is filled up with
    zeros. Uninitialized memory before the first and after the last valid bytes
    are not saved. Up to 64 KiB or 16 MiB with long address.

    Useful for small ROM files.

-f, --flat
    Flat address space output mode.

    Overlapping blocks are flattened and uninitialized memory is filled up with
    zeros. Uninitialized memory after the last valid byte is not saved. Up to
    4 GiB.

    Useful for creating huge multi bank ROM files. See sections for an example.

-n, --nonlinear
    Generate nonlinear output file.

    Overlapping blocks are flattened. Blocks are saved in sorted order and
    uninitialized memory is skipped. Up to 64 KiB or 16 MiB with long address.

    Used for linkers and downloading.

    64tass --nonlinear a.asm
    *       = $1000
            lda #2
    *       = $2000
            nop

          Result of compilation
    $02, $00 little endian length, 2 bytes
    $00, $10 little endian start $1000
    $a9, $02 code
    $01, $00 little endian length, 1 byte
    $00, $20 little endian start $2000
    $ea      code
    $00, $00 end marker (length=0)

--atari-xex
    Generate a Atari XEX output file.

    Overlapping blocks are kept, continuing blocks are concatenated. Saving
    happens in the definition order without sorting, and uninitialized memory
    is skipped in the output. Up to 64 KiB.

    Used for Atari executables.

    64tass --atari-xex a.asm
    *       = $02e0
            .addr start      ;run address
    *       = $2000
    start   rts

          Result of compilation
    $ff, $ff header, 2 bytes
    $e0, $02 little endian start $02e0
    $e1, $02 little endian last byte $02e1
    $00, $20 start address word
    $00, $20 little endian start $2000
    $00, $20 little endian last byte $2000
    $60      code

--apple2
    Generate a Apple II output file (DOS 3.3).

    Overlapping blocks are flattened and uninitialized memory is filled up with
    zeros. Uninitialized memory before the first and after the last valid bytes
    are not saved. Up to 64 KiB.

    Used for Apple II executables.

    64tass --apple-ii a.asm
    *       = $0c00
            rts

         Result of compilation
    $00, $0c little endian start $0c00
    $01, $00 little endian length $0001
    $60      code

--intel-hex
    Use Intel HEX output file format.

    Overlapping blocks are kept, data is stored in the definition order, and
    uninitialized areas are skipped. I8HEX up to 64 KiB, I32HEX up to 4 GiB.

    Used for EPROM programming or downloading.

    64tass --intel-hex a.asm
    *       = $0c00
            rts

    Result of compilation:

    :010C00006093
    :00000001FF

--s-record
    Use Motorola S-record output file format.

    Overlapping blocks are kept, data is stored in the definition order, and
    uninitialized memory areas are skipped. S19 up to 64 KiB, S28 up to 16 MiB
    and S37 up to 4 GiB.

    Used for EPROM programming or downloading.

    64tass --s-record a.asm
    *       = $0c00
            rts

    Result of compilation:

    S1040C00608F
    S9030C00F0

Operation options

-a, --ascii
    Use ASCII/Unicode text encoding instead of raw 8-bit

    Normally no conversion takes place, this is for backwards compatibility
    with a DOS based Turbo Assembler editor, which could create PETSCII files
    for 6502tass. (including control characters of course)

    Using this option will change the default `none' and `screen' encodings to
    map 'a'-'z' and 'A'-'Z' into the correct PETSCII range of $41-$5A and
    $C1-$DA, which is more suitable for an ASCII editor. It also adds
    predefined petcat style PETSCII literals to the default encodings, and
    enables Unicode letters in symbol names.

    For writing sources in UTF-8/UTF-16 encodings this option is required!

    64tass a.asm

    .0000    a9 61          lda #$61        lda #"a"

    >0002    31 61 41                       .text "1aA"
    >0005    7b 63 6c 65 61 72 7d 74        .text "{clear}text{return}more"
    >000e    65 78 74 7b 72 65 74 75
    >0016    72 6e 7d 6d 6f 72 65

    64tass --ascii a.asm

    .0000    a9 41          lda #$41        lda #"a"
    >0002    31 41 c1                       .text "1aA"
    >0005    93 54 45 58 54 0d 4d 4f        .text "{clear}text{return}more"
    >000e    52 45

-B, --long-branch
    Automatic BXX *+5 JMP xxx. Branch too long messages are usually solved by
    manually rewriting them as BXX *+5 JMP xxx. 64tass can do this
    automatically if this option is used. BRA is of course not converted.

    64tass a.asm
    *       = $1000
            bcc $1233       ;error...

    64tass a.asm
    *       = $1000
            bcs *+5         ;opposite condition
            jmp $1233       ;as simple workaround

    64tass --long-branch a.asm
    *       = $1000
            bcc $1233       ;no error, automatically converted to the above one.

-C, --case-sensitive
    Make all symbols (variables, opcodes, directives, operators, etc.) case
    sensitive. Otherwise everything is case insensitive by default.

    64tass a.asm
    label   nop
    Label   nop     ;double defined...

    64tass --case-sensitive a.asm
    label   nop
    Label   nop     ;Ok, it's a different label...

-D <label>=<value>
    Command line definition.

    Same syntax is allowed as in source files. Be careful with strings, the
    shell might eat the quotes unless escaped.

    Using hexadecimal numbers might be tricky as the shell might try to expand
    them as variables. Either quoting or backslash escaping might help.

    In Makefiles all $ signs need to be escaped by doubling them. This needs to
    be done over the normal shell escaping. For example `$1000' becomes `\
    $$1000'.

    64tass -D ii=2 -D var=\"string\" -D FAST:=true a.asm
            lda #ii ;result: $a9, $02
    FAST    :?= false ;define if undefined

-w, --no-warn
    Suppress warnings.

    Disables warnings during compile. For fine grained diagnostic message
    suppression see the diagnostic options section.

    64tass --no-warn a.asm

--no-caret-diag
    Suppress displaying of faulty source line and fault position after fault
    messages.

    This is for cases where the fault log is automatically processed and no one
    ever looks at it and therefore there's no point to display the source
    lines.

    64tass --no-caret-diag a.asm

--macro-caret-diag
    Restrict source line and fault position display to macro expansions only.

    This is for cases where the fault log is processed by an editor which also
    displays the compilation output somewhere. Only lines which are the result
    of macro processing will be output to aid debugging. Those which would just
    duplicate what's in the source editor window will be not.

    64tass --macro-caret-diag a.asm

-q, --quiet
    Suppress messages. Disables header and summary messages.

    64tass --quiet a.asm

-T, --tasm-compatible
    Enable TASM compatible operators and precedence

    Switches the expression evaluator into compatibility mode. This enables
    `.', `:' and `!' operators and disables 64tass specific extensions,
    disables precedence handling and forces 16 bit unsigned evaluation (see
    `differences to original Turbo Assembler' below)

-I <path>
    Specify include search path

    If an included source or binary file can't be found in the directory of the
    source file then this path is tried. More than one directories can be
    specified by repeating this option. If multiple matches exist the first one
    is used.

-M <file>, --dependencies <file>
    Specify make rule output file

    Writes a dependency rules suitable for `make' from the list of files used
    during compilation.

--make-phony
    Enable phony targets for dependencies

    This is useful for automatic dependency generation to avoid missing target
    errors on file rename.

    The following Makefile uses the rules generated by 64tass (in `.dep') to
    achieve automatic dependency tracking:

    demo: demo.asm .dep
            64tass --make-phony -M.dep $< -o $@

    .dep:
    -include .dep

-E <file>, --error <file>
    Specify error output file

    Normally compilation errors a written to the standard error output. It's
    possible to redirect them to a file or to the standard output by using `-'
    as the file name.

Diagnostic options

Diagnostic message switched start with a `-W' and can have an optional `no-'
prefix to disable them. The options below with this prefix are enabled by
default, the others are disabled.

-Wall
    Enable most diagnostic warnings, except those individually disabled. Or
    with the `no-' prefix disable all except those enabled.
-Werror
    Make all diagnostic warnings to an error, except those individually set to
    a warning.
-Werror=<name>
    Change a diagnostic warning to an error.

    For example `-Werror=implied-reg' makes this check an error. The
    `-Wno-error=' variant is useful with `-Werror' to set some to warnings.

-Walias
    Warns about alias opcodes.

    There are several opcodes for the same task, especially for the "6502i"
    target.

-Waltmode
    Warn about alternative address modes.

    Sometimes alternative addressing modes are used as the fitting one is not
    available. For example there's no lda direct page y so instead data bank y
    is used with a warning.

-Wbranch-page
    Warns if a branch is crossing a page.

    Page crossing branches execute with a penalty cycle. This option helps to
    locate them easily.

-Wcase-symbol
    Warn if symbol letter case is used inconsistently.

    This option can be used to enforce letter case matching of symbols in case
    insensitive mode. This gives similar results to the case sensitive mode
    (symbols must match exactly) with the main difference of disallowing symbol
    name definitions differing only in case (these are reported as duplicates).

-Wimmediate
    Warns for cases where immediate addressing is more likely.

    It may be hard to notice if a `#' was missed. The code still compiles but
    there's a huge difference between `cpx #const' and `cpx const'. Unless the
    right sort of garbage was on zero page at the time of testing...

    This check might have a lot of false positives if zero page locations are
    accessed by using small numbers, which is a popular coding style. But there
    are ways to reduce them.

    For "known" fixed locations address(x) can be used, preferably bound to a
    symbol. Automatic allocation of zero page variables works too (e.g. zpstuff
    .byte ?). And basically everything which is a traditional "label" or
    derived from a label with an offset.

-Wimplied-reg
    Warns if implied addressing is used instead of register.

    Some instructions have implied aliases like `asl' for `asl a' for
    compatibility reasons, but this shorthand is not the preferred form.

-Wleading-zeros
    Warns if about leading zeros.

    A leading zero could be a prefix for an octal number but as octals are not
    supported the result will be decimal.

-Wlong-branch
    Warns when a long branch is used.

    This option gives a warning for instructions which were modified by the
    long branch function. Less intrusive than disabling long branches and see
    where it fails.

-Wmacro-prefix
    Warn about macro call without prefix.

    Such macro calls can easily be mistaken to be labels if invoked without
    parameters. Also it's hard to notice that an unchanged call turned into
    label after the definition got renamed. This warning helps to find such
    calls so that prefixes can be added.

-Wno-deprecated
    Don't warn about deprecated features.

    Unfortunately there were some features added previously which shouldn't
    have been included. This option disables warnings about their uses.

-Wno-float-compare
    Don't warn if floating point comparisons are only approximate.

    Floating point numbers have a finite precision and comparing them might
    give unexpected results.

    For example 2.1 + 0.2 == 2.3 is true but gives a warning as the left side
    is actually bigger by approximately 4.44E-16.

    Normally this is solved by rounding or changing the comparison values.

-Wfloat-round
    Warn when floating point numbers are implicitly rounded.

    A lot of parameters and the data dumping directives need integers but
    floating point numbers are accepted as well. The style of rounding used may
    or may not be what you wanted.

    By default floor rounding (to lower) is used and not truncate (towards
    zero). The reason for this is to enable calculation of fixed point integers
    by using floating point.

    The difference is subtle and only noticable for negative numbers. The
    division of -300/256 is -2 which matches floor(-300/256.0) but not trunc
    (-300/256.0).

    To get symmetric sine waves around zero trunc() needs to be used. Some
    other calculation might result in 126.9999997 due to inaccuracies in
    logarithm which would need round().

    To avoid unexpected rounding this option helps to find those places where
    no explicit rounding was done.

-Wno-ignored
    Don't warn about ignored directives.
-Wno-jmp-bug
    Don't warn about the jmp ($xxff) bug.

    With this option it's fine that the high byte is read from the `wrong'
    address on a 6502, NMOS 6502 and 65DTV02.

-Wno-label-left
    Don't warn about certain labels not being on left side.

    You may disable this if you use labels which look like mistyped versions of
    implied addressing mode instructions and you don't want to put them in the
    first column.

    This check is there to catch typos, unsupported implied instructions, or
    unknown aliases and not for enforcing label placement.

-Wno-pitfalls
    Don't note about common pitfalls.

    There are some common mistakes, but experts and those who read this don't
    need extra notes about them. These are:

    Use multi character strings with `.byte' instead of `.text'.
        This fails because `.byte' enforces the 0-255 range for each value.
    Using `label *=*+1' style space reservations.
        Warns as `*=' is also the compound multiply operator. The `*=*+1' needs
        to be on a separate line without a label. A better alternatively is to
        use `.fill 1' or `.byte ?'.
    Negative numbers with `.byte' or `.word'
        There are other directives which accept them with proper range checks
        like `.char', `.sint'.
    Negative numbers with `lda #xxx'
        There's a signed variant for the immediate addressing so `lda #+xx'
        will make it work

-Wno-star-assign
    Don't warn about ignored compound multiply.

    Normally `symbol *= ...' means compound multiply of the variable in front.
    Unfortunately this looks the same a `label *=*+x' which is an old-school
    way to allocate space.

    If the symbol was a variable defined earlier then the multiply is performed
    without a warning. If it's a new label definition then this warning is used
    to note that maybe a variable definition was missed earlier.

    If the intention was really a label definition then the `*=' can be moved
    to a separate line, or in case of space allocation it could be improved to
    use `.byte ?' or `.fill x'.

-Wold-equal
    Warn about old equal operator.

    The single `=' operator is only there for compatibility reasons and should
    be written as `==' normally.

-Woptimize
    Warn about optimizable code.

    Warns on things that could be optimized, at least according to the limited
    analysis done. Currently it's easy to fool with these constructs:

      + Self modifying code, especially modifying immediate addressing mode
        instructions or branch targets
      + Using .byte $2c and similar tricks to skip instructions.
      + Using *+5 and similar tricks to skip instructions, or to loop like *-1.
      + Any other method of flow control not involving referenced labels. E.g.
        calculated returns.
      + Register re-mappings on 65DTV02 with SIR and SAC.

    It's also rather simple and conservative, so some opportunities will be
    missed. Most CPUs are supported with the notable exception of 65816 and
    65EL02, but this could improve in later versions.

-Wno-page
    Don't do an error for page crossing

    Normally the .page directive gives an error on page crossing, this
    directive can disable it. Using `-Wno-error=page' can turn it into a
    warning only.

-Wno-portable
    Don't warn about source portability problems.

    These cross platform development annoyances are checked for:

      + Case insensitive use of file names or use of short names.
      + Use of backslashes for path separation instead of forward slashes.
      + Use of reserved characters in file names.
      + Absolute paths
-Wshadow
    Warn about symbol shadowing.

    Checks if local variables `shadow' other variables of same name in upper
    scopes in ambiguous ways.

    This is useful to detect hard to notice bugs where a new local variable
    takes the place of a global one by mistake.

    bl      .block
    a       .byte 2         ;'a' is a built-in register
    x       .byte 2         ;'x' is a built-in register
            asl a           ; accumulator or the byte above?
            .end
            asl bl.x        ; not ambiguous

-Wstrict-bool
    Warn about implicit boolean conversions.

    Boolean values can be interpreted as numeric 0/1 and other types as
    booleans. This is convenient but may cause mistakes.

    To pass this option the following constructs need improvements:

      + `1' and `0' as boolean constants. Use the slightly longer `true' and
        `false'.
      + Implicit non-zero checks. Write it out like `.if (lbl & 1) != 0'.
      + Zero checks with `!'. Write it out like `lbl == 0'.
      + Binary operators on booleans. Use the proper `||', `&&' and `^^'
        operators.
      + Numeric expressions like `1 + (lbl > 3)'. It's better as `(lbl > 3) ? 2
        : 1'.
-Wswitch-case
    Warn about multiple switch case matches

    A switch value can match several case conditions but only the first
    occurance will compile. A second match might be a mistake.

-Wunused
    Warn about unused constant symbols.

    Symbols which have no references to them are likely redundant. Before
    removing them check if there's any conditionally compiled out code which
    might still need them.

    The following options can be used to be more specific:

    -Wunused-macro
        Warn about unused macros.
    -Wunused-const
        Warn about unused constants.
    -Wunused-label
        Warn about unused labels.
    -Wunused-variable
        Warn about unused variables.

    Symbols which appear in a default 64tass symbol list file and their root
    symbols are treated as used for exporting purposes.

-Wno-wrap-addr
    Don't warn about memory location address space wrap around.

    Applying offsets to memory locations may result in addresses which end up
    outside of the processors address space.

    For example "tmp" is at $1000 and then it's addressed as lda tmp-$2000 then
    the result will be lda $f000 or lda $fff000 depending on the CPU. If this
    is fine then this warning can be disabled otherwise it can be made into an
    error by using -Werror=wrap-addr.

-Wno-wrap-bank0
    Don't warn for bank 0 wrap around.

    Adding an offset to a bank 0 address may end up outside of bank 0. If this
    happens a warning is issued and the address wraps around.

    The warning may be ignored using this command line parameter. Alternatively
    it could be turned into an error by using -Werror=wrap-bank0.

-Wno-wrap-dpage
    Don't warn for direct page wrap around.

    Adding an offset to a direct page address may end up outside of the direct
    page. For a 65816 or 65EL02 an alternative addressing mode is used but on
    other processors if this happens a warning is issued and the address wraps
    around.

    The warning may be ignored using this command line parameter. Alternatively
    it could be turned into an error by using -Werror=wrap-dpage.

-Wno-wrap-mem
    Don't warn for compile offset wrap around.

    While assembling the compile offset may reach the end of memory image. If
    this happens a warning is issued and the compile offset is set to the start
    of image.

    The warning may be ignored using this command line parameter. Alternatively
    it could be turned into an error by using -Werror=wrap-mem.

    The image size depends on the output format. See the Output options section
    above.

-Wno-wrap-pc
    Don't warn for program counter wrap around.

    While assembling the program counter may reach the end of the current
    program bank. If this happens a warning is issued and the address wraps
    around.

    The warning may be ignored using this command line parameter. Alternatively
    it could be turned into an error by using -Werror=wrap-pc.

-Wno-wrap-pbank
    Don't warn for program bank address calculation wrap around.

    Adding an offset to a program bank address may end up outside of the
    current program bank. If this happens a warning is issued and the address
    wraps around.

    The warning may be ignored using this command line parameter. Alternatively
    it could be turned into an error by using -Werror=wrap-pbank.

Target selection on command line

These options will select the default architecture. It can be overridden by
using the .cpu directive in the source.

--m65xx
    Standard 65xx (default). For writing compatible code, no extra codes. This
    is the default.

    64tass --m65xx a.asm
            lda $14         ;regular instructions

-c, --m65c02
    CMOS 65C02. Enables extra opcodes and addressing modes specific to this
    CPU.

    64tass --m65c02 a.asm
            stz $d020       ;65c02 instruction

--m65ce02
    CSG 65CE02. Enables extra opcodes and addressing modes specific to this
    CPU.

    64tass --m65ce02 a.asm
            inz

-i, --m6502
    NMOS 65xx. Enables extra illegal opcodes. Useful for demo coding for C64,
    disk drive code, etc.

    64tass --m6502 a.asm
            lax $14         ;illegal instruction

-t, --m65dtv02
    65DTV02. Enables extra opcodes specific to DTV.

    64tass --m65dtv02 a.asm
            sac #$00

-x, --m65816
    W65C816. Enables extra opcodes. Useful for SuperCPU projects.

    64tass --m65816 a.asm
            lda $123456,x

-e, --m65el02
    65EL02. Enables extra opcodes, useful RedPower CPU projects. Probably
    you'll need `--nostart' as well.

    64tass --m65el02 a.asm
            lda #0,r

--mr65c02
    R65C02. Enables extra opcodes and addressing modes specific to this CPU.

    64tass --mr65c02 a.asm
            rmb 7,$20

--mw65c02
    W65C02. Enables extra opcodes and addressing modes specific to this CPU.

    64tass --mw65c02 a.asm
            wai

--m4510
    CSG 4510. Enables extra opcodes and addressing modes specific to this CPU.
    Useful for C65 projects.

    64tass --m4510 a.asm
            map
            eom

Symbol listing

-l <file>, --labels=<file>
    List symbols into <file>.

    64tass -l labels.txt a.asm
    *       = $1000
    label   jmp label

    result (labels.txt):
    label           = $1000

    This option may be used multiple times. In this case the format and root
    scope options must be placed before this option. Using the same name
    multiple times is not a good idea.

    64tass --vice-labels -l all.l --export-labels --labels-root=export -l myexport.inc source.asm

    This writes symbols for VICE into `all.l' and symbols from scope `export'
    into `myexport.inc'.

--labels-root=<path>
    Specify the scope to list labels from

    This option can be used to limit the output to only a subset of labels. The
    parameter is a dot separated path to a scope started from the global scope.

--normal-labels
    Lists labels in a 64tass readable format. (default)

    List labels without any side effects. Usually for display purposes or for
    later include.

--export-labels
    List labels for include in a 64tass readable format.

    The difference to normal symbol listing is that 64tass assumes these
    symbols will be used in another source. In practice this means that any
    .proc/.pend blocks appearing in the symbol file will always be compiled
    even if unused otherwise.

--vice-labels
    List labels in a VICE readable format.

    This format may be used to translate memory locations to something readable
    in VICE monitor. Therefore simple numeric constants will not show up unless
    converted to an address first.

    VICE symbols may only contain ASCII letters, numbers and underscore.
    Symbols not meeting this requirement will be omitted.

    If a memory location has several symbols only one will be included in the
    label list.

    64tass --vice-labels -l labels.l a.asm
    *       = $1000
    label   jmp label

    result (labels.l):
    al 1000 .label

    For now colons are used as scope delimiter due to a VICE limitation, but
    this will be changed to dots in the future.

--vice-labels-numeric
    List address like symbols in a VICE readable format including numeric
    constants.

    The normal VICE label list does not include symbols like chrout = $ffd2 or
    keybuff = 631 as these are numeric constants and not memory addresses.

    Of course there are ways around that. For example:

    chrout  = address($ffd2)
    keybuff = address(631)
    *       = $ffd2
    chrout  .fill 3
    *       = 631
    keybuff .fill 10

    For those who don't want to waste time on explicitly marking addresses as
    such there's an easy way out by using this command line option.

    The tradeoff is that depending on the coding style the label list will
    become polluted by non-address constants to various degrees. However if one
    mostly uses numeric constants for addresses only this may be acceptable.

--dump-labels
    List labels for debugging.

    The output will contain symbol locations and paths.

Assembly listing

-L <file>, --list=<file>
    List into <file>. Dumps source code and compiled code into file. Useful for
    debugging, it's much easier to identify the code in memory within the
    source files.

    ; 64tass Turbo Assembler Macro V1.5x listing file
    ; 64tass -L list.txt a.asm
    ; Fri Dec  9 19:08:55 2005

    ;Offset ;Hex            ;Monitor        ;Source

    ;******  Processing input file: a.asm

    .1000   a2 00           ldx #$00                ldx #0
    .1002   ca              dex             loop    dex
    .1003   d0 fd           bne $1002               bne loop
    .1005   60              rts                     rts

    ;******  End of listing

-m, --no-monitor
    Don't put monitor code into listing. There won't be any monitor listing in
    the list file.

    ; 64tass Turbo Assembler Macro V1.5x listing file
    ; 64tass --no-monitor -L list.txt a.asm
    ; Fri Dec  9 19:11:43 2005

    ;Offset ;Hex            ;Source

    ;******  Processing input file: a.asm

    .1000   a2 00                   ldx #0
    .1002   ca              loop    dex
    .1003   d0 fd                   bne loop
    .1005   60                      rts

    ;******  End of listing

-s, --no-source
    Don't put source code into listing. There won't be any source listing in
    the list file.

    ; 64tass Turbo Assembler Macro V1.5x listing file
    ; 64tass --no-source -L list.txt a.asm
    ; Fri Dec  9 19:13:25 2005

    ;Offset ;Hex            ;Monitor

    ;******  Processing input file: a.asm

    .1000   a2 00           ldx #$00
    .1002   ca              dex
    .1003   d0 fd           bne $1002
    .1005   60              rts

    ;******  End of listing

--line-numbers
    This option creates a new column for showing line numbers for easier
    identification of source origin. The line number is followed with an
    optional colon separated file number in case it comes from a different file
    then the previous lines.

    ; 64tass Turbo Assembler Macro V1.5x listing file
    ; 64tass --line-numbers -L list.txt a.asm
    ; Fri Dec  9 19:13:25 2005

    ;Line   ;Offset ;Hex            ;Monitor        ;Source

    :1      ;******  Processing input file: a.asm

    3       .1000   a2 00           ldx #$00                ldx #0
    4       .1002   ca              dex             loop    dex
    5       .1003   d0 fd           bne $1002               bne loop
    6       .1005   60              rts                     rts

    ;******  End of listing

--tab-size=<number>
    By default the listing file is using a tab size of 8 to align the
    disassembly. This can be changed to other more favorable values like 4.
    Only spaces are used if 1 is selected. Please note that this has no effect
    on the source code on the right hand side.
--verbose-list
    Normally the assembler tries to minimize listing output by omitting
    "unimportant" lines. But sometimes it's better to just list everything
    including comments and empty lines.

    ; 64tass Turbo Assembler Macro V1.5x listing file
    ; 64tass --verbose-list -L list.txt a.asm
    ; Fri Dec  9 19:13:25 2005

    ;Offset ;Hex            ;Monitor        ;Source

    ;******  Processing input file: a.asm

                                            *       = $1000

    .1000   a2 00           ldx #$00                ldx #0
    .1002   ca              dex             loop    dex
    .1003   d0 fd           bne $1002               bne loop
    .1005   60              rts                     rts

    ;******  End of listing

Other options

-?, --help
    Give this help list. Prints help about command line options.
--usage
    Give a short usage message. Prints short help about command line options.
-V, --version
    Print program version

Command line from file

Command line arguments can be read from a file as well. This is useful to store
common options for multiple files in one place or to overcome the argument list
length limitations of some systems.

The filename needs to be prefixed with an at sign, so `@argsfile' reads options
from `argsfile'. It will only work if there's not another file named
`@argsfile'. The content is expanded in-place of `@argsfile'.

Stored options must be separated by white space. Single or double quotes can be
used in case file names have white space in their names.

Backslash can be used to escape the character following it and it must be used
to escape itself. Single and double quotes need to be escaped if needed for
string quoting.

Forward slashes can be used as a portable path separation on all systems.

-------------------------------------------------------------------------------

Messages

Faults and warnings encountered are sent to the standard error for logging. To
redirect them to a file append `2>filename.log' after the command or use the `
-E' command line option. The message format is the following:

<filename>:<line>:<character>: <severity>: <message>

  * filename: The name and path of source file where the error happened.
  * line: Line number in file, starts from 1.
  * character: Character in line, starts from 1. Tabs are not expanded.
  * severity: Note, warning, error or fatal.
  * message: The fault message itself.

The faulty line will be displayed after the message with a caret pointing to
the error location unless this is disabled by using `--no-caret-diag' option.

a.asm:3:21: error: not defined ident 'label'
                 lda label
                     ^
a.asm:3:21: note: searched in the global scope

This is helpful for macro expansions as it displays the processed line which
usually looks different to the one in the original source file.

Error buried deep in included files or macros display a backtrace of files
after an `In file included from' text where all the files and positions
involved are listed down to the main file.

In file included from main.asm:3:3:
included.asm:2:11: error: not defined ident 'test'
                #macro1 test
                        ^
In file included from included.asm:2:3,
                      main.asm:3:3:
macros.asm:3:7: note: original location in an expanded macro was here
                lda test
                    ^

Messages ending with `[-Wxxx]' are user controllable. This means that using
`-Wno-xxx' on the command line will silence them and `-Werror=xxx' will turn
them it into a fault. See Diagnostic options for more details.

Warnings

approximate floating point
    floating point comparisons are not exact and the numbers were close but
    maybe not quite
bank 0 address overflow
    the calculated memory location address ended up outside of bank 0 and is
    now wrapped.
case ignored, value already handled
    this value was already used in an earlier case so here it's ignored
compile offset overflow
    compile continues at the bottom ($0000) as end of compile area was reached
constant result, possibly changeable to 'lda'
    a pre-calculated value could be loaded instead as the result seems to be
    always the same
could be shorter by using 'xxx' instead
    this shorter instruction gives the same result according to the optimizer
could be simpler by using 'xxx' instead
    this instruction gives the same result but with less dependencies according
    to the optimizer
deprecated directive, only for TASM compatible mode
    .goto and .lbl should only be used in TASM compatible mode and there are
    better ways to loop
deprecated equal operator, use '==' instead
    single equal sign for comparisons is going away soon, update source
deprecated modulo operator, use '%' instead
    double slash for modulo is going away soon, update source
deprecated not equal operator, use '!=' instead
    non-standard not equal operators which will stop working in the future,
    update source
direct page address overflow
    the calculated memory location address ended up outside of direct page and
    is now wrapped.
directive ignored
    an assembler directive was ignored for compatibility reasons
expected ? values but got ? to unpack
    the number of variables must match the number of values when unpacking
immediate addressing mode suggested
    numeric constant was used as an address which was likely meant as an
    immediate value
implicit floating point rounding
    a floating point number with fractional part was used for an integer
    parameter
independent result, possibly changeable to 'lda'
    the result does not seem to depend on the input so it could be just loaded
    instead
instruction 'xxx' is an alias of 'xxx'
    an alternative instruction name was used
label defined instead of variable multiplication for compatibility
    move the '*=' construct to a separate line or define the variable first as
    this construct is ambiguous
label not on left side
    check if an instruction name was not mistyped and if the current CPU has
    it, or remove white space before label
leading zeros ignored
    leading zeros in front of decimals are redundant and don't denote an octal
    number
long branch used
    branch distance was too long so long branch was used (bxx *+5 jmp)
memory location address overflow
    the calculated memory location address ended up outside of the processors
    address space
please use format("%d", ...) as '^' will change it's meaning
    this operator will be changed to mean the bank byte later, please update
    your sources
please use quotes now to allow expressions in future
    the directive will allow expressions later and the parameter will be a
    string
possible jmp ($xxff) bug
    some 6502 variants read don't increment the high byte on page cross and
    this may be unexpected
possibly redundant as ...
    according to the optimizer this might not be needed
possibly redundant if last 'jsr' is changed to 'jmp'
    tail call elimination possibility was detected
possibly redundant indexing with a constant value
    the index register used seems to be constant and there's a way to eliminate
    indexing by a constant offset
processor program counter overflow
    pc address was set back to the start of actual 64 KiB program bank as end
    of bank was reached
program bank address overflow
    the calculated memory location address ended up outside of the current
    program bank and is now wrapped.
symbol case mismatch '?'
    the symbol is matching case insensitively but it's not all letters are
    exactly the same
the file's real name is not '?'
    check if all characters match including their case as this is not the real
    name of the file
this name uses reserved characters '?'
    do not use \ : * ? " < > | in file names as some operating systems don't
    like these
unused symbol '?'
    this symbol has is not referred anywhere and therefore may be unused
use '/' as path separation '?'
    backslash is not a path separator on all systems while forward slash will
    work independent of the host operating system
use relative path for '?'
    file's path is absolute and depends on the file system layout and the
    source will not compile without the exact same environment

Errors

'?' expected
    something is missing
? argument is missing
    not enough arguments supplied
address in different program bank
    this instruction is only limited to access the current bank
address not in processor address space
    value larger than current CPU address space
address out of section
    moving the address around is fine as long as it does not end up before the
    start of the section
addressing mode too complex
    too much indexing or indirection for a valid address
at least one byte is needed
    the expression didn't yield any bytes but it's needed here
branch crosses page by ? bytes
    page crossing was on branch was detected
branch too far by ? bytes
    branches have limited range and this went over by some bytes
can't calculate stable value
    somehow it's impossible to calculate this expression
can't calculate this
    could not get any value, is this a circular reference?
can't encode character '?' ($xx) in encoding '?'
    can't translate character in this encoding as no definition was given
can't get absolute value of
    not possible to calculate the absolute value of this type
can't get boolean value of
    not possible to determine if this value is true or false
can't get integer value of
    this value is not a number
can't get length of
    this type has no length
can't get sign of
    this type does not have a sign as it's not a number
can't get size of
    this type has no size
closing/opening directive '?' not found
    couldn't find the other half of block directive pair
conflict
    at least one feature is provided, which shouldn't be there
conversion of ? '?' to ? is not possible
    this type conversion can't be done
division by zero
    dividing with zero can't be done
double defined escape
    escape sequence already defined in another .edef differently
double defined range
    part of a character range was already defined by another .cdef and these
    ranges can't overlap
duplicate definition
    symbol defined more than once
empty encoding, add something or correct name
    probably a typo in the name of encoding but if not then use .cdef/.edef to
    define something
empty list not allowed
    at least one element is required
empty range not allowed
    invalid range but there must be at least one element
empty string not allowed
    at least one character is required
expected exactly/at least/at most ? arguments, got ?
    wrong number of function arguments used
expression syntax
    syntax error
extra characters on line
    there's some garbage on the end of line
floating point overflow
    infinity reached during a calculation
general syntax
    can't do anything with this
index out of range
    not enough elements in list
key error
    key not in the dictionary
label required
    a label is mandatory for this directive
last byte must not be gap
    .shift or .shiftl needs a normal byte at the end
logarithm of non-positive number
    only positive numbers have a logarithm
macro call without prefix
    macro call was found without a prefix and without parameters
more than a single character
    no more than a single character is allowed
more than two characters
    no more than two characters are allowed
most significant bit must be clear in byte
    for .shift and .shiftl only 7 bit "bytes" are valid
must be used within a loop
    .break or .continue must be used within a loop
negative number raised on fractional power
    can't calculate this
no ? addressing mode for opcode 'xxx'
    this addressing mode is not valid for this instruction
not a bank 0 address
    value must be a bank zero address
not a data bank address
    value must be a data bank address
not a direct page address
    value must be a direct page address
not a key and value pair
    dictionaries are built from key and value pairs separated by a colon
not a variable
    only variables are changeable
not allowed here: ?
    do not use this directive here
not defined '?'
    can't find this label at this point
not hashable
    the type can't be used as a key in a dictionary
not in range -1.0 to 1.0
    the function is only valid in the -1.0 to 1.0 range
not iterable
    value is not a list or other iterable object
offset out of range
    code offset too much
operands could not be broadcast together with shapes ? and ?
    list length must match or must have a single element only
different start and end page $xxxx and $xxxx
    page crossing was detected
ptext too long by ? bytes
    .ptext is limited to 255 bytes maximum
requirements not met
    not all features are provided, at least one is missing
reserved symbol name '?'
    do not use this symbol name
shadow definition
    symbol is defined in an upper scope as well and is used ambiguously
some operation '?' of type '?' and type '?' not possible
    can't do this calculation with these values
square root of negative number
    can't calculate the square root of a negative number
too large for a ? bit signed/unsigned integer
    value out of range
unknown processor '?'
    unknown cpu name
unknown argument name '?'
    no parameter argument known like this
value needs to be non-negative
    only positive numbers or zero is accepted here
wrong type <?>
    wrong object type used
zero value not allowed
    do not use zero for example with .null

Fatal errors

can't open file
    cannot open file
can't write error file
    cannot write the error file
can't write label file
    cannot write the label file
can't write listing file
    cannot write the list file
can't write make file
    cannot write the make rule file
can't write object file
    cannot write the result
error reading file
    error while reading
file recursion
    wrong nesting of .include
function recursion too deep
    wrong use of nested functions
macro recursion too deep
    wrong use of nested macros
option '?' doesn't allow an argument
    command line option doesn't need any argument
option '?' is ambiguous
    command line option abbreviation is too short
option '?' not recognized
    no such command line option
option '?' requires an argument
    command line option needs an argument
out of memory
    won't happen ;)
scope '?' for label listing not found
    the scope given on command line couldn't be found
section '?' for output not found
    the section given on command line couldn't be found
too many passes
    with a carefully crafted source file it's possible to create unresolvable
    situations but try to avoid this
unknown option '?'
    option not known
weak recursion
    excessive nesting of .weak

-------------------------------------------------------------------------------

Credits

Original 6502tass written for DOS by Marek Matula of Taboo.

It was ported to ANSI C by BigFoot/Breeze. This is when it's name changed to
64tass.

Soci/Singular reworked the code over the years to the point that practically
nothing was left from original at this point.

Improved TASS compatibility, PETSCII codes by Groepaz.

Additional code: my_getopt command-line argument parser by Benjamin Sittler,
avl tree code by Franck Bui-Huu, ternary tree code by Daniel Berlin, snprintf
Alain Magloire, Amiga OS4 support files by Janne Per?aho.

Pierre Zero helped to uncover a lot of faults by fuzzing. Also there were a lot
of discussions with oziphantom about the need of various features.

Main developer and maintainer: soci at c64.rulez.org

-------------------------------------------------------------------------------

Default translation and escape sequences

Raw 8-bit source

By default raw 8-bit encoding is used and nothing is translated or escaped.
This mode is for compiling sources which are already PETSCII.

The `none' encoding for raw 8-bit

Does no translation at all, no translation table, no escape sequences.

The `screen' encoding for raw 8-bit

The following translation table applies, no escape sequences.

           Built-in PETSCII to PETSCII screen code translation table
       Input               Byte                Input               Byte
00-1F               80-9F               20-3F               20-3F
40-5F               00-1F               60-7F               40-5F
80-9F               80-9F               A0-BF               60-7F
C0-FE               40-7E               FF                  5E

Unicode and ASCII source

Unicode encoding is used when the `-a' option is given on the command line.

The `none' encoding for Unicode

This is a Unicode to PETSCII mapping, including escape sequences for control
codes.

                 Built-in Unicode to PETSCII translation table
 Glyph          Unicode          Byte    Glyph          Unicode          Byte
 -@      U+0020-U+0040         20-40    A-Z      U+0041-U+005A         C1-DA
[        U+005B                5B       ]        U+005D                5D
a-z      U+0061-U+007A         41-5A    ?        U+00A3                5C
?        U+03C0                FF       ?        U+2190                5F
?        U+2191                5E       ?        U+2500                C0
?        U+2502                DD       ?        U+250C                B0
?        U+2510                AE       ?        U+2514                AD
?        U+2518                BD       ?        U+251C                AB
?        U+2524                B3       ?        U+252C                B2
?        U+2534                B1       ?        U+253C                DB
?        U+256D                D5       ?        U+256E                C9
?        U+256F                CB       ?        U+2570                CA
?        U+2571                CE       ?        U+2572                CD
?        U+2573                D6       ?        U+2581                A4
?        U+2582                AF       ?        U+2583                B9
?        U+2584                A2       ?        U+258C                A1
?        U+258D                B5       ?        U+258E                B4
?        U+258F                A5       ?        U+2592                A6
?        U+2594                A3       ?        U+2595                A7
?        U+2596                BB       ?        U+2597                AC
?        U+2598                BE       ?        U+259A                BF
?        U+259D                BC       ?        U+25CB                D7
?        U+25CF                D1       ?        U+25E4                A9
?        U+25E5                DF       ?        U+2660                C1
?        U+2663                D8       ?        U+2665                D3
?        U+2666                DA       ?        U+2713                BA
?        U+1FB70               D4       ?        U+1FB71               C7
?        U+1FB72               C2       ?        U+1FB73               DD
?        U+1FB74               C8       ?        U+1FB75               D9
?        U+1FB76               C5       ?        U+1FB77               C4
?        U+1FB78               C3       ?        U+1FB79               C0
?        U+1FB7A               C6       ?        U+1FB7B               D2
?        U+1FB7C               CC       ?        U+1FB7D               CF
?        U+1FB7E               D0       ?        U+1FB7F               BA
?        U+1FB82               B7       ?        U+1FB83               B8
?        U+1FB87               AA       ?        U+1FB88               B6
?        U+1FB8C               DC       ?        U+1FB8F               A8
?        U+1FB95               FF       ?        U+1FB98               DF
?        U+1FB99               A9

                       Built-in PETSCII escape sequences
      Escape       Byte         Escape        Byte          Escape         Byte
{bell}             07    {black}              90    {blk}                  90
{blue}             1F    {blu}                1F    {brn}                  95
{brown}            95    {cbm-*}              DF    {cbm-+}                A6
{cbm--}            DC    {cbm-0}              30    {cbm-1}                81
{cbm-2}            95    {cbm-3}              96    {cbm-4}                97
{cbm-5}            98    {cbm-6}              99    {cbm-7}                9A
{cbm-8}            9B    {cbm-9}              29    {cbm-@}                A4
{cbm-^}            DE    {cbm-a}              B0    {cbm-b}                BF
{cbm-c}            BC    {cbm-d}              AC    {cbm-e}                B1
{cbm-f}            BB    {cbm-g}              A5    {cbm-h}                B4
{cbm-i}            A2    {cbm-j}              B5    {cbm-k}                A1
{cbm-l}            B6    {cbm-m}              A7    {cbm-n}                AA
{cbm-o}            B9    {cbm-pound}          A8    {cbm-p}                AF
{cbm-q}            AB    {cbm-r}              B2    {cbm-s}                AE
{cbm-t}            A3    {cbm-up arrow}       DE    {cbm-u}                B8
{cbm-v}            BE    {cbm-w}              B3    {cbm-x}                BD
{cbm-y}            B7    {cbm-z}              AD    {clear}                93
{clr}              93    {control-0}          92    {control-1}            90
{control-2}        05    {control-3}          1C    {control-4}            9F
{control-5}        9C    {control-6}          1E    {control-7}            1F
{control-8}        9E    {control-9}          12    {control-:}            1B
{control-;}        1D    {control-=}          1F    {control-@}            00
{control-a}        01    {control-b}          02    {control-c}            03
{control-d}        04    {control-e}          05    {control-f}            06
{control-g}        07    {control-h}          08    {control-i}            09
{control-j}        0A    {control-k}          0B    {control-left arrow}   06
{control-l}        0C    {control-m}          0D    {control-n}            0E
{control-o}        0F    {control-pound}      1C    {control-p}            10
{control-q}        11    {control-r}          12    {control-s}            13
{control-t}        14    {control-up arrow}   1E    {control-u}            15
{control-v}        16    {control-w}          17    {control-x}            18
{control-y}        19    {control-z}          1A    {cr}                   0D
{cyan}             9F    {cyn}                9F    {delete}               14
{del}              14    {dish}               08    {down}                 11
{ensh}             09    {esc}                1B    {f10}                  82
{f11}              84    {f12}                8F    {f1}                   85
{f2}               89    {f3}                 86    {f4}                   8A
{f5}               87    {f6}                 8B    {f7}                   88
{f8}               8C    {f9}                 80    {gray1}                97
{gray2}            98    {gray3}              9B    {green}                1E
{grey1}            97    {grey2}              98    {grey3}                9B
{grn}              1E    {gry1}               97    {gry2}                 98
{gry3}             9B    {help}               84    {home}                 13
{insert}           94    {inst}               94    {lblu}                 9A
{left arrow}       5F    {left}               9D    {lf}                   0A
{lgrn}             99    {lower case}         0E    {lred}                 96
{lt blue}          9A    {lt green}           99    {lt red}               96
{orange}           81    {orng}               81    {pi}                   FF
{pound}            5C    {purple}             9C    {pur}                  9C
{red}              1C    {return}             0D    {reverse off}          92
{reverse on}       12    {rght}               1D    {right}                1D
{run}              83    {rvof}               92    {rvon}                 12
{rvs off}          92    {rvs on}             12    {shift return}         8D
{shift-*}          C0    {shift-+}            DB    {shift-,}              3C
{shift--}          DD    {shift-.}            3E    {shift-/}              3F
{shift-0}          30    {shift-1}            21    {shift-2}              22
{shift-3}          23    {shift-4}            24    {shift-5}              25
{shift-6}          26    {shift-7}            27    {shift-8}              28
{shift-9}          29    {shift-:}            5B    {shift-;}              5D
{shift-@}          BA    {shift-^}            DE    {shift-a}              C1
{shift-b}          C2    {shift-c}            C3    {shift-d}              C4
{shift-e}          C5    {shift-f}            C6    {shift-g}              C7
{shift-h}          C8    {shift-i}            C9    {shift-j}              CA
{shift-k}          CB    {shift-l}            CC    {shift-m}              CD
{shift-n}          CE    {shift-o}            CF    {shift-pound}          A9
{shift-p}          D0    {shift-q}            D1    {shift-r}              D2
{shift-space}      A0    {shift-s}            D3    {shift-t}              D4
{shift-up arrow}   DE    {shift-u}            D5    {shift-v}              D6
{shift-w}          D7    {shift-x}            D8    {shift-y}              D9
{shift-z}          DA    {space}              20    {sret}                 8D
{stop}             03    {swlc}               0E    {swuc}                 8E
{tab}              09    {up arrow}           5E    {up/lo lock off}       09
{up/lo lock on}    08    {upper case}         8E    {up}                   91
{white}            05    {wht}                05    {yellow}               9E
{yel}              9E

The `screen' encoding for Unicode

This is a Unicode to PETSCII screen code mapping, including escape sequences
for control code screen codes.

           Built-in Unicode to PETSCII screen code translation table
 Glyph       Unicode       Translated    Glyph       Unicode       Translated
 -?     U+0020-U+003F     20-3F         @       U+0040            00
A-Z     U+0041-U+005A     41-5A         [       U+005B            1B
]       U+005D            1D            a-z     U+0061-U+007A     01-1A
?       U+00A3            1C            ?       U+03C0            5E
?       U+2190            1F            ?       U+2191            1E
?       U+2500            40            ?       U+2502            5D
?       U+250C            70            ?       U+2510            6E
?       U+2514            6D            ?       U+2518            7D
?       U+251C            6B            ?       U+2524            73
?       U+252C            72            ?       U+2534            71
?       U+253C            5B            ?       U+256D            55
?       U+256E            49            ?       U+256F            4B
?       U+2570            4A            ?       U+2571            4E
?       U+2572            4D            ?       U+2573            56
?       U+2581            64            ?       U+2582            6F
?       U+2583            79            ?       U+2584            62
?       U+258C            61            ?       U+258D            75
?       U+258E            74            ?       U+258F            65
?       U+2592            66            ?       U+2594            63
?       U+2595            67            ?       U+2596            7B
?       U+2597            6C            ?       U+2598            7E
?       U+259A            7F            ?       U+259D            7C
?       U+25CB            57            ?       U+25CF            51
?       U+25E4            69            ?       U+25E5            5F
?       U+2660            41            ?       U+2663            58
?       U+2665            53            ?       U+2666            5A
?       U+2713            7A            ?       U+1FB70           54
?       U+1FB71           47            ?       U+1FB72           42
?       U+1FB73           5D            ?       U+1FB74           48
?       U+1FB75           59            ?       U+1FB76           45
?       U+1FB77           44            ?       U+1FB78           43
?       U+1FB79           40            ?       U+1FB7A           46
?       U+1FB7B           52            ?       U+1FB7C           4C
?       U+1FB7D           4F            ?       U+1FB7E           50
?       U+1FB7F           7A            ?       U+1FB82           77
?       U+1FB83           78            ?       U+1FB87           6A
?       U+1FB88           76            ?       U+1FB8C           5C
?       U+1FB8F           68            ?       U+1FB95           5E
?       U+1FB98           5F            ?       U+1FB99           69

                 Built-in PETSCII screen code escape sequences
   Escape      Byte         Escape         Byte          Escape           Byte
{cbm-*}       5F     {cbm-+}              66     {cbm--}                 5C
{cbm-0}       30     {cbm-9}              29     {cbm-@}                 64
{cbm-^}       5E     {cbm-a}              70     {cbm-b}                 7F
{cbm-c}       7C     {cbm-d}              6C     {cbm-e}                 71
{cbm-f}       7B     {cbm-g}              65     {cbm-h}                 74
{cbm-i}       62     {cbm-j}              75     {cbm-k}                 61
{cbm-l}       76     {cbm-m}              67     {cbm-n}                 6A
{cbm-o}       79     {cbm-pound}          68     {cbm-p}                 6F
{cbm-q}       6B     {cbm-r}              72     {cbm-s}                 6E
{cbm-t}       63     {cbm-up arrow}       5E     {cbm-u}                 78
{cbm-v}       7E     {cbm-w}              73     {cbm-x}                 7D
{cbm-y}       77     {cbm-z}              6D     {left arrow}            1F
{pi}          5E     {pound}              1C     {shift-*}               40
{shift-+}     5B     {shift-,}            3C     {shift--}               5D
{shift-.}     3E     {shift-/}            3F     {shift-0}               30
{shift-1}     21     {shift-2}            22     {shift-3}               23
{shift-4}     24     {shift-5}            25     {shift-6}               26
{shift-7}     27     {shift-8}            28     {shift-9}               29
{shift-:}     1B     {shift-;}            1D     {shift-@}               7A
{shift-^}     5E     {shift-a}            41     {shift-b}               42
{shift-c}     43     {shift-d}            44     {shift-e}               45
{shift-f}     46     {shift-g}            47     {shift-h}               48
{shift-i}     49     {shift-j}            4A     {shift-k}               4B
{shift-l}     4C     {shift-m}            4D     {shift-n}               4E
{shift-o}     4F     {shift-pound}        69     {shift-p}               50
{shift-q}     51     {shift-r}            52     {shift-space}           60
{shift-s}     53     {shift-t}            54     {shift-up arrow}        5E
{shift-u}     55     {shift-v}            56     {shift-w}               57
{shift-x}     58     {shift-y}            59     {shift-z}               5A
{space}       20     {up arrow}           1E

-------------------------------------------------------------------------------

Opcodes

Standard 6502 opcodes

                           The standard 6502 opcodes
ADC 61 65 69 6D 71 75 79 7D             AND 21 25 29 2D 31 35 39 3D
ASL 06 0A 0E 16 1E                      BCC 90
BCS B0                                  BEQ F0
BIT 24 2C                               BMI 30
BNE D0                                  BPL 10
BRK 00                                  BVC 50
BVS 70                                  CLC 18
CLD D8                                  CLI 58
CLV B8                                  CMP C1 C5 C9 CD D1 D5 D9 DD
CPX E0 E4 EC                            CPY C0 C4 CC
DEC C6 CE D6 DE                         DEX CA
DEY 88                                  EOR 41 45 49 4D 51 55 59 5D
INC E6 EE F6 FE                         INX E8
INY C8                                  JMP 4C 6C
JSR 20                                  LDA A1 A5 A9 AD B1 B5 B9 BD
LDX A2 A6 AE B6 BE                      LDY A0 A4 AC B4 BC
LSR 46 4A 4E 56 5E                      NOP EA
ORA 01 05 09 0D 11 15 19 1D             PHA 48
PHP 08                                  PLA 68
PLP 28                                  ROL 26 2A 2E 36 3E
ROR 66 6A 6E 76 7E                      RTI 40
RTS 60                                  SBC E1 E5 E9 ED F1 F5 F9 FD
SEC 38                                  SED F8
SEI 78                                  STA 81 85 8D 91 95 99 9D
STX 86 8E 96                            STY 84 8C 94
TAX AA                                  TAY A8
TSX BA                                  TXA 8A
TXS 9A                                  TYA 98

                         Aliases, pseudo instructions
ASL 0A                                  BGE B0
BLT 90                                  CPA C1 C5 C9 CD D1 D5 D9 DD
GCC 4C 90                               GCS 4C B0
GEQ 4C F0                               GGE 4C B0
GLT 4C 90                               GMI 30 4C
GNE 4C D0                               GPL 10 4C
GVC 4C 50                               GVS 4C 70
LSR 4A                                  ROL 2A
ROR 6A                                  SHL 06 0A 0E 16 1E
SHR 46 4A 4E 56 5E

-------------------------------------------------------------------------------

6502 illegal opcodes

This processor is a standard 6502 with the NMOS illegal opcodes.

                              Additional opcodes
ANC 0B                                  ANE 8B
ARR 6B                                  ASR 4B
DCP C3 C7 CF D3 D7 DB DF                ISB E3 E7 EF F3 F7 FB FF
JAM 02                                  LAX A3 A7 AB AF B3 B7 BF
LDS BB                                  NOP 04 0C 14 1C 80
RLA 23 27 2F 33 37 3B 3F                RRA 63 67 6F 73 77 7B 7F
SAX 83 87 8F 97                         SBX CB
SHA 93 9F                               SHS 9B
SHX 9E                                  SHY 9C
SLO 03 07 0F 13 17 1B 1F                SRE 43 47 4F 53 57 5B 5F

                              Additional aliases
AHX 93 9F                               ALR 4B
AXS CB                                  DCM C3 C7 CF D3 D7 DB DF
INS E3 E7 EF F3 F7 FB FF                ISC E3 E7 EF F3 F7 FB FF
LAE BB                                  LAS BB
LXA AB                                  TAS 9B
XAA 8B

-------------------------------------------------------------------------------

65DTV02 opcodes

This processor is an enhanced version of standard 6502 with some illegal
opcodes.

                     Additionally to 6502 illegal opcodes
BRA 12                                  SAC 32
SIR 42

                         Additional pseudo instruction
GRA 12 4C

                      These illegal opcodes are not valid
ANC 0B                                  JAM 02
LDS BB                                  NOP 04 0C 14 1C 80
SBX CB                                  SHA 93 9F
SHS 9B                                  SHX 9E
SHY 9C

                          These aliases are not valid
AHX 93 9F                               AXS CB
LAE BB                                  LAS BB
TAS 9B

-------------------------------------------------------------------------------

Standard 65C02 opcodes

This processor is an enhanced version of standard 6502.

                              Additional opcodes
ADC 72                                  AND 32
BIT 34 3C 89                            BRA 80
CMP D2                                  DEC 3A
EOR 52                                  INC 1A
JMP 7C                                  LDA B2
ORA 12                                  PHX DA
PHY 5A                                  PLX FA
PLY 7A                                  SBC F2
STA 92                                  STZ 64 74 9C 9E
TRB 14 1C                               TSB 04 0C

                  Additional aliases and pseudo instructions
CLR 64 74 9C 9E                         CPA D2
DEA 3A                                  GRA 4C 80
INA 1A

-------------------------------------------------------------------------------

R65C02 opcodes

This processor is an enhanced version of standard 65C02.

Please note that the bit number is not part of the instruction name (like rmb7
$20). Instead it's the first element of coma separated parameters (e.g. rmb
7,$20).

                              Additional opcodes
BBR 0F 1F 2F 3F 4F 5F 6F 7F             BBS 8F 9F AF BF CF DF EF FF
NOP 44 54 82 DC                         RMB 07 17 27 37 47 57 67 77
SMB 87 97 A7 B7 C7 D7 E7 F7

-------------------------------------------------------------------------------

W65C02 opcodes

This processor is an enhanced version of R65C02.

                              Additional opcodes
STP DB                                  WAI CB

                              Additional aliases
HLT DB

-------------------------------------------------------------------------------

W65816 opcodes

This processor is an enhanced version of 65C02.

                              Additional opcodes
ADC 63 67 6F 73 77 7F                   AND 23 27 2F 33 37 3F
BRL 82                                  CMP C3 C7 CF D3 D7 DF
COP 02                                  EOR 43 47 4F 53 57 5F
JMP 5C DC                               JSL 22
JSR FC                                  LDA A3 A7 AF B3 B7 BF
MVN 54                                  MVP 44
ORA 03 07 0F 13 17 1F                   PEA F4
PEI D4                                  PER 62
PHB 8B                                  PHD 0B
PHK 4B                                  PLB AB
PLD 2B                                  REP C2
RTL 6B                                  SBC E3 E7 EF F3 F7 FF
SEP E2                                  STA 83 87 8F 93 97 9F
STP DB                                  TCD 5B
TCS 1B                                  TDC 7B
TSC 3B                                  TXY 9B
TYX BB                                  WAI CB
WDM 42                                  XBA EB
XCE FB

                              Additional aliases
CLP C2                                  CPA C3 C7 CF D3 D7 DF
CSP 02                                  HLT DB
JML 5C DC                               SWA EB
TAD 5B                                  TAS 1B
TDA 7B                                  TSA 3B

-------------------------------------------------------------------------------

65EL02 opcodes

This processor is an enhanced version of standard 65C02.

                              Additional opcodes
ADC 63 67 73 77                         AND 23 27 33 37
CMP C3 C7 D3 D7                         DIV 4F 5F 6F 7F
ENT 22                                  EOR 43 47 53 57
JSR FC                                  LDA A3 A7 B3 B7
MMU EF                                  MUL 0F 1F 2F 3F
NXA 42                                  NXT 02
ORA 03 07 13 17                         PEA F4
PEI D4                                  PER 62
PHD DF                                  PLD CF
REA 44                                  REI 54
REP C2                                  RER 82
RHA 4B                                  RHI 0B
RHX 1B                                  RHY 5B
RLA 6B                                  RLI 2B
RLX 3B                                  RLY 7B
SBC E3 E7 F3 F7                         SEA 9F
SEP E2                                  STA 83 87 93 97
STP DB                                  SWA EB
TAD BF                                  TDA AF
TIX DC                                  TRX AB
TXI 5C                                  TXR 8B
TXY 9B                                  TYX BB
WAI CB                                  XBA EB
XCE FB                                  ZEA 8F

                              Additional aliases
CLP C2                                  CPA C3 C7 D3 D7
HLT DB

-------------------------------------------------------------------------------

65CE02 opcodes

This processor is an enhanced version of R65C02.

                              Additional opcodes
ASR 43 44 54                            ASW CB
BCC 93                                  BCS B3
BEQ F3                                  BMI 33
BNE D3                                  BPL 13
BRA 83                                  BSR 63
BVC 53                                  BVS 73
CLE 02                                  CPZ C2 D4 DC
DEW C3                                  DEZ 3B
INW E3                                  INZ 1B
JSR 22 23                               LDA E2
LDZ A3 AB BB                            NEG 42
PHW F4 FC                               PHZ DB
PLZ FB                                  ROW EB
RTS 62                                  SEE 03
STA 82                                  STX 9B
STY 8B                                  TAB 5B
TAZ 4B                                  TBA 7B
TSY 0B                                  TYS 2B
TZA 6B

                              Additional aliases
ASR 43                                  BGE B3
BLT 93                                  NEG 42
RTN 62

                            This alias is not valid
CLR 64 74 9C 9E

-------------------------------------------------------------------------------

CSG 4510 opcodes

This processor is an enhanced version of 65CE02.

                              Additional opcodes
MAP 5C

                              Additional aliases
EOM EA

-------------------------------------------------------------------------------

Appendix

Assembler directives

.addr .al .align .as .assert .autsiz .bend .binary .binclude .bfor .block
.break .breakif .brept .bwhile .byte .case .cdef .cerror .char .check .comment
.continue .continueif .cpu .cwarn .databank .default .dint .dpage .dsection
.dstruct .dunion .dword .edef .else .elsif .enc .end .endc .endf .endif .endm
.endn .endp .ends .endswitch .endu .endv .endweak .endwith .eor .error .fi
.fill .for .function .goto .here .hidemac .if .ifeq .ifmi .ifne .ifpl .include
.lbl .lint .logical .long .macro .mansiz .namespace .next .null .offs .option
.page .pend .proc .proff .pron .ptext .rept .rta .section .seed .segment .send
.shift .shiftl .showmac .sint .struct .switch .text .union .var .virtual .warn
.weak .while .with .word .xl .xs

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Built-in functions

abs acos all any asin atan atan2 binary cbrt ceil cos cosh deg exp floor format
frac hypot len log log10 pow rad random range repr round sign sin sinh size
sort sqrt tan tanh trunc

Built-in types

address bits bool bytes code dict float gap int list str tuple type

